CVE-2026-98038

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-98038", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:19:56.071Z", "datePublished": "2026-09-25T10:23:51.746Z", "dateUpdated": "2026-10-21T12:54:09.561Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:54:09.561Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Keep refcount_acquire nullable for borrowed RCU kptrs\n\nbpf_refcount_acquire() is fallible for a borrowed reference because the\nobject may have reached a zero refcount. The verifier therefore keeps\nKF_RET_NULL on the return value unless the argument is an owning reference.\n\nAn RCU-protected load of a local kptr is marked MEM_ALLOC, but it only\nreceives NON_OWN_REF when the pointee contains a graph node. A refcounted\nobject without a graph node consequently looks like an owning reference\neven though the loaded register has no acquired reference state. If the\nprogram drops the last real reference while remaining in the RCU critical\nsection, refcount_inc_not_zero() returns NULL while the verifier treats the\nresult as non-NULL.\n\nOnly classify the argument as owning when it is backed by a verifier-tracked\nreference. This retains the non-NULL return for pointers from bpf_obj_new(),\nbpf_kptr_xchg(), or an earlier successful acquisition, while requiring a\nNULL check for borrowed RCU kptrs.\n\n[ kkd: Rewrote commit log ]"}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/bpf/verifier.c"], "versions": [{"version": "1b12171533a9bb23cf6fba7262b479028b65e1e8", "lessThan": "85bfc8b6db43502444c428eaa2de20bdd2fb9064", "status": "affected", "versionType": "git"}, {"version": "1b12171533a9bb23cf6fba7262b479028b65e1e8", "lessThan": "8d19e2cdfba9ba8c8eb6a459cd666bec00a1d2c6", "status": "affected", "versionType": "git"}, {"version": "1b12171533a9bb23cf6fba7262b479028b65e1e8", "lessThan": "85074498228a2500ea8b8039c49cc1ab8ad5328f", "status": "affected", "versionType": "git"}, {"version": "1b12171533a9bb23cf6fba7262b479028b65e1e8", "lessThan": "dc36739e5cc9f60485418a910b42bc95339218d2", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/bpf/verifier.c"], "versions": [{"version": "6.8", "status": "affected"}, {"version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.114", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.7", "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": "6.8", "versionEndExcluding": "6.12.114"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.18.57"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.2.7"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/85bfc8b6db43502444c428eaa2de20bdd2fb9064"}, {"url": "https://git.kernel.org/stable/c/8d19e2cdfba9ba8c8eb6a459cd666bec00a1d2c6"}, {"url": "https://git.kernel.org/stable/c/85074498228a2500ea8b8039c49cc1ab8ad5328f"}, {"url": "https://git.kernel.org/stable/c/dc36739e5cc9f60485418a910b42bc95339218d2"}], "title": "bpf: Keep refcount_acquire nullable for borrowed RCU kptrs", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["kernel/bpf/verifier.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "85bfc8b6db43502444c428eaa2de20bdd2fb9064", "status": "affected", "version": "1b12171533a9bb23cf6fba7262b479028b65e1e8", "versionType": "git"}, {"lessThan": "8d19e2cdfba9ba8c8eb6a459cd666bec00a1d2c6", "status": "affected", "version": "1b12171533a9bb23cf6fba7262b479028b65e1e8", "versionType": "git"}, {"lessThan": "85074498228a2500ea8b8039c49cc1ab8ad5328f", "status": "affected", "version": "1b12171533a9bb23cf6fba7262b479028b65e1e8", "versionType": "git"}, {"lessThan": "dc36739e5cc9f60485418a910b42bc95339218d2", "status": "affected", "version": "1b12171533a9bb23cf6fba7262b479028b65e1e8", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["kernel/bpf/verifier.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.8"}, {"lessThan": "6.8", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.114", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.57", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.7", "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\nbpf: Keep refcount_acquire nullable for borrowed RCU kptrs\n\nbpf_refcount_acquire() is fallible for a borrowed reference because the\nobject may have reached a zero refcount. The verifier therefore keeps\nKF_RET_NULL on the return value unless the argument is an owning reference.\n\nAn RCU-protected load of a local kptr is marked MEM_ALLOC, but it only\nreceives NON_OWN_REF when the pointee contains a graph node. A refcounted\nobject without a graph node consequently looks like an owning reference\neven though the loaded register has no acquired reference state. If the\nprogram drops the last real reference while remaining in the RCU critical\nsection, refcount_inc_not_zero() returns NULL while the verifier treats the\nresult as non-NULL.\n\nOnly classify the argument as owning when it is backed by a verifier-tracked\nreference. This retains the non-NULL return for pointers from bpf_obj_new(),\nbpf_kptr_xchg(), or an earlier successful acquisition, while requiring a\nNULL check for borrowed RCU kptrs.\n\n[ kkd: Rewrote commit log ]"}], "id": "CVE-2026-98038", "lastModified": "2026-10-21T13:21:19.710", "metrics": {}, "published": "2026-09-25T11:17:32.560", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/85074498228a2500ea8b8039c49cc1ab8ad5328f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/85bfc8b6db43502444c428eaa2de20bdd2fb9064"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8d19e2cdfba9ba8c8eb6a459cd666bec00a1d2c6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/dc36739e5cc9f60485418a910b42bc95339218d2"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: bpf: Keep refcount_acquire nullable for borrowed RCU kptrs", "id": "2541135", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2541135"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-476", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nbpf: Keep refcount_acquire nullable for borrowed RCU kptrs\nbpf_refcount_acquire() is fallible for a borrowed reference because the\nobject may have reached a zero refcount. The verifier therefore keeps\nKF_RET_NULL on the return value unless the argument is an owning reference.\nAn RCU-protected load of a local kptr is marked MEM_ALLOC, but it only\nreceives NON_OWN_REF when the pointee contains a graph node. A refcounted\nobject without a graph node consequently looks like an owning reference\neven though the loaded register has no acquired reference state. If the\nprogram drops the last real reference while remaining in the RCU critical\nsection, refcount_inc_not_zero() returns NULL while the verifier treats the\nresult as non-NULL.\nOnly classify the argument as owning when it is backed by a verifier-tracked\nreference. This retains the non-NULL return for pointers from bpf_obj_new(),\nbpf_kptr_xchg(), or an earlier successful acquisition, while requiring a\nNULL check for borrowed RCU kptrs.\n[ kkd: Rewrote commit log ]", "A flaw was found in the Linux kernel's Berkeley Packet Filter (BPF) subsystem. When validating programs that manage shared reference-counted objects, the BPF verifier incorrectly treats borrowed references as always valid and fails to require null-pointer checks. A local user can exploit this vulnerability by loading a crafted BPF program, triggering a null-pointer dereference that causes a kernel crash and Denial of Service (DoS)."], "name": "CVE-2026-98038", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-09-25T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-98038\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-98038\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98038.mbox"], "threat_severity": "Low"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1b12171533a9bb23cf6fba7262b479028b65e1e8,85074498228a2500ea8b8039c49cc1ab8ad5328f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1b12171533a9bb23cf6fba7262b479028b65e1e8,dc36739e5cc9f60485418a910b42bc95339218d2)"}}], "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": "generic", "value": "6.8"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.8)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.7,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.3-rc2,*]"}}], "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": "2026-09-25T16:00:18.017828+00:00", "updated": "2026-09-30T14:30:18.585733+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}