CVE-2026-89542

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89542", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.722Z", "datePublished": "2026-09-11T19:44:18.931Z", "dateUpdated": "2026-10-19T08:48:33.941Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:48:33.941Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: harden gss_krb5_unwrap_v2 against short tokens\n\ngss_krb5_unwrap_v2() reads the EC and RRC header fields at ptr+4 and\nptr+6 before validating that the token is at least GSS_KRB5_TOK_HDR_LEN\n(16) bytes long, and its rotate_left() helper passes buf->len - base\nto xdr_buf_subsegment() without verifying that base <= buf->len. When\na caller hands in a sub-16-byte token, or a token whose declared len\nleaves base past the end of the buffer, three distinct failures follow:\n\n gss_krb5_unwrap_v2(offset, len, buf)\n ptr = buf->head[0].iov_base + offset\n ec = *(ptr + 4) /* OOB read on short head */\n rrc = *(ptr + 6) /* OOB read on short head */\n rotate_left(offset + 16, buf, rrc)\n xdr_buf_subsegment(buf, &subbuf,\n base, buf->len - base) /* u32 wrap when base > len */\n _rotate_left(&subbuf, shift)\n shift %= buf->len /* divide-by-zero when base == len */\n\nAfter decryption, the cleanup arithmetic has the same shape:\n\n movelen = min_t(unsigned int, buf->head[0].iov_len, len);\n movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;\n BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >\n buf->head[0].iov_len);\n\nThe BUG_ON re-adds the value just subtracted, so it reduces to\nmin(A, B) > A and is permanently false; it cannot catch the unsigned\nunderflow of movelen, which then drives a ~UINT_MAX-byte memmove().\n\nAdd four defense-in-depth guards inside the unwrap core so it is safe\nregardless of what its callers validate:\n\n - reject tokens with len - offset < GSS_KRB5_TOK_HDR_LEN before\n touching ptr+4/ptr+6;\n - bail from rotate_left() when buf->len <= base, covering both the\n underflow and zero-length cases;\n - return early from _rotate_left() when buf->len is zero, so the\n shift %= buf->len modulo cannot fault;\n - replace the dead BUG_ON with a live check that returns\n GSS_S_DEFECTIVE_TOKEN before the movelen subtraction."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - gss_krb5_unwrap_v2() is reached from nfsd RPCSEC_GSS privacy unwrap (svcauth_gss_accept \u2192 svcauth_gss_unwrap_priv \u2192 gss_unwrap) on TCP/2049 and from the NFS client gss_unwrap_resp_priv() path on a krb5p Reply, so a remote RPCSEC_GSS peer delivers the crafted wrap token over the network.\nAC:L - A single crafted RPCSEC_GSS DATA/Reply with a sub-16-byte wrap token (KG2_TOK_WRAP, sealed flags, non-zero RRC) deterministically hits the pre-decrypt ptr+4/ptr+6 reads, rotate_left() u32 wrap, and shift%=0 divide-by-zero; no race or attacker-uncontrollable layout is required.\nPR:N - A malicious NFS server on an existing krb5p session needs no account or capability on the victim client to send the crafted Reply into gss_unwrap_resp_priv(). That client-victim path is the highest-severity reachability and requires no privileges on the target.\nUI:N - nfsd unwraps the Call in the service thread with no local user action. On the client, gss_unwrap_resp_priv() runs automatically from the RPC receive path once an NFS/RPCSEC_GSS mount exists; no additional mount, click, or open is required at attack time.\nS:U - The out-of-bounds accesses, divide-by-zero, and underflowed memmove corrupt host kernel SUNRPC/GSS state on the machine processing the RPC. This is ordinary same-host kernel impact, not a VM escape, IOMMU bypass, or other changed-scope boundary.\nC:H - Short tokens make gss_krb5_unwrap_v2() read EC/RRC past the token, and the dead BUG_ON lets unsigned movelen underflow into a ~UINT_MAX-byte memmove() that copies kernel memory beyond the receive head; that unbounded read is C:H per kernel CNA memory-corruption guidance.\nI:H - The same underflowed memmove() writes near 4GiB through the RPC receive head, an out-of-bounds write exploitable for control-flow hijack. rotate_left() also ignores xdr_buf_subsegment() failure after u32 wrap and then writes through a subbuf whose length has wrapped.\nA:H - _rotate_left() does shift %= buf->len on a zero-length subbuffer (header-only token at the XDR boundary), a divide-by-zero oops/panic; the UINT_MAX memmove and wrapped-length rotate loop hang or oops nfsd/rpciod, and the attacker can repeat the RPC to deny service."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/sunrpc/auth_gss/gss_krb5_wrap.c"], "versions": [{"version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "299d281c7225ded15b28cb861a98d818d82787fc", "status": "affected", "versionType": "git"}, {"version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "84ddbc8d084c0251d534f14f5d1a7da05be56404", "status": "affected", "versionType": "git"}, {"version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "075d7cfc4df8c54cb202ba8b28420370c03ba9b6", "status": "affected", "versionType": "git"}, {"version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "f2591660e0eb263c9415bf0d0bb1b111e62df7a4", "status": "affected", "versionType": "git"}, {"version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "dddcb0f4b7e27fac16a78ea9a1c8ec2e8a241087", "status": "affected", "versionType": "git"}, {"version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "806584a4b67a7233870c33e5b8f872e76dd02988", "status": "affected", "versionType": "git"}, {"version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "a7894e10572d53eb10109b8d07459cc8d3435811", "status": "affected", "versionType": "git"}, {"version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "6959297aaa9572783d620a226d73c3fb94494888", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/sunrpc/auth_gss/gss_krb5_wrap.c"], "versions": [{"version": "2.6.35", "status": "affected"}, {"version": "0", "lessThan": "2.6.35", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "5.10.270"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "5.15.221"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "6.1.188"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "6.6.157"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "6.12.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/299d281c7225ded15b28cb861a98d818d82787fc"}, {"url": "https://git.kernel.org/stable/c/84ddbc8d084c0251d534f14f5d1a7da05be56404"}, {"url": "https://git.kernel.org/stable/c/075d7cfc4df8c54cb202ba8b28420370c03ba9b6"}, {"url": "https://git.kernel.org/stable/c/f2591660e0eb263c9415bf0d0bb1b111e62df7a4"}, {"url": "https://git.kernel.org/stable/c/dddcb0f4b7e27fac16a78ea9a1c8ec2e8a241087"}, {"url": "https://git.kernel.org/stable/c/806584a4b67a7233870c33e5b8f872e76dd02988"}, {"url": "https://git.kernel.org/stable/c/a7894e10572d53eb10109b8d07459cc8d3435811"}, {"url": "https://git.kernel.org/stable/c/6959297aaa9572783d620a226d73c3fb94494888"}], "title": "SUNRPC: harden gss_krb5_unwrap_v2 against short tokens", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-89542", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T19:23:31.016705Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:42.330Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-89542", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T19:23:31.016705Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:23:31.599Z"}}], "cna": {"title": "SUNRPC: harden gss_krb5_unwrap_v2 against short tokens", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 9.8, "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "AV:N - gss_krb5_unwrap_v2() is reached from nfsd RPCSEC_GSS privacy unwrap (svcauth_gss_accept \u2192 svcauth_gss_unwrap_priv \u2192 gss_unwrap) on TCP/2049 and from the NFS client gss_unwrap_resp_priv() path on a krb5p Reply, so a remote RPCSEC_GSS peer delivers the crafted wrap token over the network.\nAC:L - A single crafted RPCSEC_GSS DATA/Reply with a sub-16-byte wrap token (KG2_TOK_WRAP, sealed flags, non-zero RRC) deterministically hits the pre-decrypt ptr+4/ptr+6 reads, rotate_left() u32 wrap, and shift%=0 divide-by-zero; no race or attacker-uncontrollable layout is required.\nPR:N - A malicious NFS server on an existing krb5p session needs no account or capability on the victim client to send the crafted Reply into gss_unwrap_resp_priv(). That client-victim path is the highest-severity reachability and requires no privileges on the target.\nUI:N - nfsd unwraps the Call in the service thread with no local user action. On the client, gss_unwrap_resp_priv() runs automatically from the RPC receive path once an NFS/RPCSEC_GSS mount exists; no additional mount, click, or open is required at attack time.\nS:U - The out-of-bounds accesses, divide-by-zero, and underflowed memmove corrupt host kernel SUNRPC/GSS state on the machine processing the RPC. This is ordinary same-host kernel impact, not a VM escape, IOMMU bypass, or other changed-scope boundary.\nC:H - Short tokens make gss_krb5_unwrap_v2() read EC/RRC past the token, and the dead BUG_ON lets unsigned movelen underflow into a ~UINT_MAX-byte memmove() that copies kernel memory beyond the receive head; that unbounded read is C:H per kernel CNA memory-corruption guidance.\nI:H - The same underflowed memmove() writes near 4GiB through the RPC receive head, an out-of-bounds write exploitable for control-flow hijack. rotate_left() also ignores xdr_buf_subsegment() failure after u32 wrap and then writes through a subbuf whose length has wrapped.\nA:H - _rotate_left() does shift %= buf->len on a zero-length subbuffer (header-only token at the XDR boundary), a divide-by-zero oops/panic; the UINT_MAX memmove and wrapped-length rotate loop hang or oops nfsd/rpciod, and the attacker can repeat the RPC to deny service."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "299d281c7225ded15b28cb861a98d818d82787fc", "versionType": "git"}, {"status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "84ddbc8d084c0251d534f14f5d1a7da05be56404", "versionType": "git"}, {"status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "075d7cfc4df8c54cb202ba8b28420370c03ba9b6", "versionType": "git"}, {"status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "f2591660e0eb263c9415bf0d0bb1b111e62df7a4", "versionType": "git"}, {"status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "dddcb0f4b7e27fac16a78ea9a1c8ec2e8a241087", "versionType": "git"}, {"status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "806584a4b67a7233870c33e5b8f872e76dd02988", "versionType": "git"}, {"status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "a7894e10572d53eb10109b8d07459cc8d3435811", "versionType": "git"}, {"status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "lessThan": "6959297aaa9572783d620a226d73c3fb94494888", "versionType": "git"}], "programFiles": ["net/sunrpc/auth_gss/gss_krb5_wrap.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "2.6.35"}, {"status": "unaffected", "version": "0", "lessThan": "2.6.35", "versionType": "semver"}, {"status": "unaffected", "version": "5.10.270", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.221", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.188", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.157", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.109", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.50", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.2.4", "versionType": "semver", "lessThanOrEqual": "7.2.*"}, {"status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["net/sunrpc/auth_gss/gss_krb5_wrap.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/299d281c7225ded15b28cb861a98d818d82787fc"}, {"url": "https://git.kernel.org/stable/c/84ddbc8d084c0251d534f14f5d1a7da05be56404"}, {"url": "https://git.kernel.org/stable/c/075d7cfc4df8c54cb202ba8b28420370c03ba9b6"}, {"url": "https://git.kernel.org/stable/c/f2591660e0eb263c9415bf0d0bb1b111e62df7a4"}, {"url": "https://git.kernel.org/stable/c/dddcb0f4b7e27fac16a78ea9a1c8ec2e8a241087"}, {"url": "https://git.kernel.org/stable/c/806584a4b67a7233870c33e5b8f872e76dd02988"}, {"url": "https://git.kernel.org/stable/c/a7894e10572d53eb10109b8d07459cc8d3435811"}, {"url": "https://git.kernel.org/stable/c/6959297aaa9572783d620a226d73c3fb94494888"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: harden gss_krb5_unwrap_v2 against short tokens\n\ngss_krb5_unwrap_v2() reads the EC and RRC header fields at ptr+4 and\nptr+6 before validating that the token is at least GSS_KRB5_TOK_HDR_LEN\n(16) bytes long, and its rotate_left() helper passes buf->len - base\nto xdr_buf_subsegment() without verifying that base <= buf->len. When\na caller hands in a sub-16-byte token, or a token whose declared len\nleaves base past the end of the buffer, three distinct failures follow:\n\n gss_krb5_unwrap_v2(offset, len, buf)\n ptr = buf->head[0].iov_base + offset\n ec = *(ptr + 4) /* OOB read on short head */\n rrc = *(ptr + 6) /* OOB read on short head */\n rotate_left(offset + 16, buf, rrc)\n xdr_buf_subsegment(buf, &subbuf,\n base, buf->len - base) /* u32 wrap when base > len */\n _rotate_left(&subbuf, shift)\n shift %= buf->len /* divide-by-zero when base == len */\n\nAfter decryption, the cleanup arithmetic has the same shape:\n\n movelen = min_t(unsigned int, buf->head[0].iov_len, len);\n movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;\n BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >\n buf->head[0].iov_len);\n\nThe BUG_ON re-adds the value just subtracted, so it reduces to\nmin(A, B) > A and is permanently false; it cannot catch the unsigned\nunderflow of movelen, which then drives a ~UINT_MAX-byte memmove().\n\nAdd four defense-in-depth guards inside the unwrap core so it is safe\nregardless of what its callers validate:\n\n - reject tokens with len - offset < GSS_KRB5_TOK_HDR_LEN before\n touching ptr+4/ptr+6;\n - bail from rotate_left() when buf->len <= base, covering both the\n underflow and zero-length cases;\n - return early from _rotate_left() when buf->len is zero, so the\n shift %= buf->len modulo cannot fault;\n - replace the dead BUG_ON with a live check that returns\n GSS_S_DEFECTIVE_TOKEN before the movelen subtraction."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.270", "versionStartIncluding": "2.6.35"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.221", "versionStartIncluding": "2.6.35"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.188", "versionStartIncluding": "2.6.35"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.157", "versionStartIncluding": "2.6.35"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.109", "versionStartIncluding": "2.6.35"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.18.50", "versionStartIncluding": "2.6.35"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.2.4", "versionStartIncluding": "2.6.35"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.3", "versionStartIncluding": "2.6.35"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:48:33.941Z"}}}, "cveMetadata": {"cveId": "CVE-2026-89542", "state": "PUBLISHED", "dateUpdated": "2026-10-19T08:48:33.941Z", "dateReserved": "2026-09-11T19:38:34.722Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2026-09-11T19:44:18.931Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/sunrpc/auth_gss/gss_krb5_wrap.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "299d281c7225ded15b28cb861a98d818d82787fc", "status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "versionType": "git"}, {"lessThan": "84ddbc8d084c0251d534f14f5d1a7da05be56404", "status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "versionType": "git"}, {"lessThan": "075d7cfc4df8c54cb202ba8b28420370c03ba9b6", "status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "versionType": "git"}, {"lessThan": "f2591660e0eb263c9415bf0d0bb1b111e62df7a4", "status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "versionType": "git"}, {"lessThan": "dddcb0f4b7e27fac16a78ea9a1c8ec2e8a241087", "status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "versionType": "git"}, {"lessThan": "806584a4b67a7233870c33e5b8f872e76dd02988", "status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "versionType": "git"}, {"lessThan": "a7894e10572d53eb10109b8d07459cc8d3435811", "status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "versionType": "git"}, {"lessThan": "6959297aaa9572783d620a226d73c3fb94494888", "status": "affected", "version": "de9c17eb4a912c9028f7b470eb80815144883b26", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/sunrpc/auth_gss/gss_krb5_wrap.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "2.6.35"}, {"lessThan": "2.6.35", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.270", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.221", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.188", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.157", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.109", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.50", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: harden gss_krb5_unwrap_v2 against short tokens\n\ngss_krb5_unwrap_v2() reads the EC and RRC header fields at ptr+4 and\nptr+6 before validating that the token is at least GSS_KRB5_TOK_HDR_LEN\n(16) bytes long, and its rotate_left() helper passes buf->len - base\nto xdr_buf_subsegment() without verifying that base <= buf->len. When\na caller hands in a sub-16-byte token, or a token whose declared len\nleaves base past the end of the buffer, three distinct failures follow:\n\n gss_krb5_unwrap_v2(offset, len, buf)\n ptr = buf->head[0].iov_base + offset\n ec = *(ptr + 4) /* OOB read on short head */\n rrc = *(ptr + 6) /* OOB read on short head */\n rotate_left(offset + 16, buf, rrc)\n xdr_buf_subsegment(buf, &subbuf,\n base, buf->len - base) /* u32 wrap when base > len */\n _rotate_left(&subbuf, shift)\n shift %= buf->len /* divide-by-zero when base == len */\n\nAfter decryption, the cleanup arithmetic has the same shape:\n\n movelen = min_t(unsigned int, buf->head[0].iov_len, len);\n movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;\n BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >\n buf->head[0].iov_len);\n\nThe BUG_ON re-adds the value just subtracted, so it reduces to\nmin(A, B) > A and is permanently false; it cannot catch the unsigned\nunderflow of movelen, which then drives a ~UINT_MAX-byte memmove().\n\nAdd four defense-in-depth guards inside the unwrap core so it is safe\nregardless of what its callers validate:\n\n - reject tokens with len - offset < GSS_KRB5_TOK_HDR_LEN before\n touching ptr+4/ptr+6;\n - bail from rotate_left() when buf->len <= base, covering both the\n underflow and zero-length cases;\n - return early from _rotate_left() when buf->len is zero, so the\n shift %= buf->len modulo cannot fault;\n - replace the dead BUG_ON with a live check that returns\n GSS_S_DEFECTIVE_TOKEN before the movelen subtraction."}], "id": "CVE-2026-89542", "lastModified": "2026-10-19T09:17:49.160", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-89542", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-16T19:23:31.016705Z", "version": "2.0.3"}}]}, "published": "2026-09-11T20:19:37.380", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/075d7cfc4df8c54cb202ba8b28420370c03ba9b6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/299d281c7225ded15b28cb861a98d818d82787fc"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6959297aaa9572783d620a226d73c3fb94494888"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/806584a4b67a7233870c33e5b8f872e76dd02988"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/84ddbc8d084c0251d534f14f5d1a7da05be56404"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a7894e10572d53eb10109b8d07459cc8d3435811"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/dddcb0f4b7e27fac16a78ea9a1c8ec2e8a241087"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f2591660e0eb263c9415bf0d0bb1b111e62df7a4"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: SUNRPC memory corruption via crafted tokens", "id": "2532258", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532258"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.7", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:H", "status": "draft"}, "cwe": "CWE-125", "details": ["A flaw was found in the Linux kernel's SUNRPC (Sun Remote Procedure Call) implementation. This vulnerability, located in the `gss_krb5_unwrap_v2` function, arises when the system processes specially crafted short tokens or tokens with an invalid length. An attacker could exploit this by providing such a token, leading to memory corruption. This could result in a denial of service (DoS), making the system unavailable."], "name": "CVE-2026-89542", "public_date": "2026-09-11T19:44:18Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89542\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89542\nhttps://git.kernel.org/stable/c/6959297aaa9572783d620a226d73c3fb94494888\nhttps://git.kernel.org/stable/c/806584a4b67a7233870c33e5b8f872e76dd02988\nhttps://git.kernel.org/stable/c/a7894e10572d53eb10109b8d07459cc8d3435811\nhttps://git.kernel.org/stable/c/dddcb0f4b7e27fac16a78ea9a1c8ec2e8a241087"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[de9c17eb4a912c9028f7b470eb80815144883b26,dddcb0f4b7e27fac16a78ea9a1c8ec2e8a241087)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[de9c17eb4a912c9028f7b470eb80815144883b26,806584a4b67a7233870c33e5b8f872e76dd02988)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[de9c17eb4a912c9028f7b470eb80815144883b26,a7894e10572d53eb10109b8d07459cc8d3435811)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[de9c17eb4a912c9028f7b470eb80815144883b26,6959297aaa9572783d620a226d73c3fb94494888)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "2.6.35"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,2.6.35)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.109,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.50,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.4,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-12T04:30:07.741944+00:00", "updated": "2026-09-15T22:15:17.690114+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}