CVE-2026-89786

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89786", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.766Z", "datePublished": "2026-09-16T08:48:23.730Z", "dateUpdated": "2026-10-19T08:52:39.655Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:52:39.655Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix out-of-bounds read in ext4_read_inline_dir()\n\next4_read_inline_dir() can read a dirent header past the end of its inline\nbuffer, triggering a slab-out-of-bounds read during getdents64():\n\n BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry\n Read of size 2 at addr ffff88800f3dd23c by task exploit/148\n ...\n __ext4_check_dir_entry\n ext4_read_inline_dir\n iterate_dir\n\nThe dirent payload lives in a buffer of exactly inline_size bytes:\n\n\tdir_buf = kmalloc(inline_size, GFP_NOFS);\n\nbut iteration runs in a position space extra_offset bytes larger\n(extra_size = extra_offset + inline_size) so the synthetic \".\" and \"..\"\nland at their block-dir offsets. A dirent is formed at \"dir_buf + pos -\nextra_offset\", yet the ext4_check_dir_entry() length argument uses the\nlarger extra_size. A position whose dirent header would extend past\nextra_size is therefore accepted, and the rescan loop's rec_len probe and\next4_check_dir_entry() dereference de->rec_len before the entry is rejected.\n\nReject a position whose minimum-size dirent header would not fit within\nextra_size before forming de, in both the rescan and main loops, and pass\ninline_size rather than extra_size to ext4_check_dir_entry() so the length\ncheck matches the physical buffer."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - The slab OOB is in ext4_read_inline_dir(), reached from getdents64 via iterate_dir\u2192ext4_readdir. nfsd_readdir does vfs_llseek plus iterate_dir, and ksmbd QUERY_DIRECTORY also calls iterate_dir, so a remote NFS/SMB client can trigger the same path on an ext4-backed export.\nAC:L - A crafted inline directory with attacker-controlled rec_len values (or a seek/NFS cookie that lands ctx->pos near extra_size) deterministically forms a dirent past kmalloc(inline_size) and dereferences de->rec_len. No race or attacker-uncontrollable heap layout is required.\nPR:N - READDIR on a guest/anonymous ksmbd share or AUTH_SYS NFS export needs no host account or capability. Automount of a malicious volume by udisks2/systemd also requires no attacker privileges on the victim.\nUI:N - Once the crafted or inline-data ext4 volume is exported or automounted, the attacker alone issues NFS/SMB READDIR or local getdents64. No separate victim must open a file or confirm a dialog at attack time.\nS:U - The out-of-bounds read and any resulting kernel crash stay within the host kernel's security authority. This is not a VM escape, IOMMU/DMA bypass, or other cross-boundary breakout.\nC:H - ext4_check_dir_entry over-reads de->rec_len and adjacent dirent fields past the inline kmalloc buffer. If the inflated extra_size bound lets the check pass, dir_emit copies de->name for up to 255 bytes of adjacent kernel heap into the getdents/NFS/SMB reply.\nI:N - The defect is an over-read on the readdir path only. ext4_read_inline_dir does not write the over-read dirent, and there is no out-of-bounds write, type confusion, or control-flow hijack primitive.\nA:H - KASAN reports a slab-out-of-bounds read in __ext4_check_dir_entry. An over-read that reaches unmapped slab or guard pages oopses or panics the kernel, and the attacker can repeat READDIR/getdents against the crafted directory."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/ext4/inline.c"], "versions": [{"version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "lessThan": "d1e7c186555ad65554fd2f2b02f5a539aa35ae48", "status": "affected", "versionType": "git"}, {"version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "lessThan": "5fd20d4e50dd6e460b3ea8e4396f8553d4526f8f", "status": "affected", "versionType": "git"}, {"version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "lessThan": "1a1dea633b724a1c042dbcdb1fed27f410916688", "status": "affected", "versionType": "git"}, {"version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "lessThan": "b060861f662d4826dc700a1c3584243bb3474cfe", "status": "affected", "versionType": "git"}, {"version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "lessThan": "6702c7da86d8cdb88d0fc57166286e115ffeb8c0", "status": "affected", "versionType": "git"}, {"version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "lessThan": "36bf17bb90cdf7a623499b624b05acde4d2feef5", "status": "affected", "versionType": "git"}, {"version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "lessThan": "9333cc809f0a89e001b814155a6cb8903a6274df", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/ext4/inline.c"], "versions": [{"version": "3.10", "status": "affected"}, {"version": "0", "lessThan": "3.10", "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": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.52", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.6", "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": "3.10", "versionEndExcluding": "5.15.221"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "6.1.188"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "6.6.157"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "6.12.110"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "6.18.52"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "7.2.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/d1e7c186555ad65554fd2f2b02f5a539aa35ae48"}, {"url": "https://git.kernel.org/stable/c/5fd20d4e50dd6e460b3ea8e4396f8553d4526f8f"}, {"url": "https://git.kernel.org/stable/c/1a1dea633b724a1c042dbcdb1fed27f410916688"}, {"url": "https://git.kernel.org/stable/c/b060861f662d4826dc700a1c3584243bb3474cfe"}, {"url": "https://git.kernel.org/stable/c/6702c7da86d8cdb88d0fc57166286e115ffeb8c0"}, {"url": "https://git.kernel.org/stable/c/36bf17bb90cdf7a623499b624b05acde4d2feef5"}, {"url": "https://git.kernel.org/stable/c/9333cc809f0a89e001b814155a6cb8903a6274df"}], "title": "ext4: fix out-of-bounds read in ext4_read_inline_dir()", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/ext4/inline.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "d1e7c186555ad65554fd2f2b02f5a539aa35ae48", "status": "affected", "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "versionType": "git"}, {"lessThan": "5fd20d4e50dd6e460b3ea8e4396f8553d4526f8f", "status": "affected", "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "versionType": "git"}, {"lessThan": "1a1dea633b724a1c042dbcdb1fed27f410916688", "status": "affected", "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "versionType": "git"}, {"lessThan": "b060861f662d4826dc700a1c3584243bb3474cfe", "status": "affected", "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "versionType": "git"}, {"lessThan": "6702c7da86d8cdb88d0fc57166286e115ffeb8c0", "status": "affected", "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "versionType": "git"}, {"lessThan": "36bf17bb90cdf7a623499b624b05acde4d2feef5", "status": "affected", "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "versionType": "git"}, {"lessThan": "9333cc809f0a89e001b814155a6cb8903a6274df", "status": "affected", "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/ext4/inline.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "3.10"}, {"lessThan": "3.10", "status": "unaffected", "version": "0", "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": "6.12.110", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.52", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.6", "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\next4: fix out-of-bounds read in ext4_read_inline_dir()\n\next4_read_inline_dir() can read a dirent header past the end of its inline\nbuffer, triggering a slab-out-of-bounds read during getdents64():\n\n BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry\n Read of size 2 at addr ffff88800f3dd23c by task exploit/148\n ...\n __ext4_check_dir_entry\n ext4_read_inline_dir\n iterate_dir\n\nThe dirent payload lives in a buffer of exactly inline_size bytes:\n\n\tdir_buf = kmalloc(inline_size, GFP_NOFS);\n\nbut iteration runs in a position space extra_offset bytes larger\n(extra_size = extra_offset + inline_size) so the synthetic \".\" and \"..\"\nland at their block-dir offsets. A dirent is formed at \"dir_buf + pos -\nextra_offset\", yet the ext4_check_dir_entry() length argument uses the\nlarger extra_size. A position whose dirent header would extend past\nextra_size is therefore accepted, and the rescan loop's rec_len probe and\next4_check_dir_entry() dereference de->rec_len before the entry is rejected.\n\nReject a position whose minimum-size dirent header would not fit within\nextra_size before forming de, in both the rescan and main loops, and pass\ninline_size rather than extra_size to ext4_check_dir_entry() so the length\ncheck matches the physical buffer."}], "id": "CVE-2026-89786", "lastModified": "2026-10-19T09:18:22.197", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.1, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.2, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-16T09:17:09.330", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1a1dea633b724a1c042dbcdb1fed27f410916688"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/36bf17bb90cdf7a623499b624b05acde4d2feef5"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5fd20d4e50dd6e460b3ea8e4396f8553d4526f8f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6702c7da86d8cdb88d0fc57166286e115ffeb8c0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9333cc809f0a89e001b814155a6cb8903a6274df"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b060861f662d4826dc700a1c3584243bb3474cfe"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d1e7c186555ad65554fd2f2b02f5a539aa35ae48"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[c4d8b0235aa98f8c26bf94d308be3fdd24154572,d1e7c186555ad65554fd2f2b02f5a539aa35ae48)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[c4d8b0235aa98f8c26bf94d308be3fdd24154572,5fd20d4e50dd6e460b3ea8e4396f8553d4526f8f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[c4d8b0235aa98f8c26bf94d308be3fdd24154572,1a1dea633b724a1c042dbcdb1fed27f410916688)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[c4d8b0235aa98f8c26bf94d308be3fdd24154572,b060861f662d4826dc700a1c3584243bb3474cfe)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[c4d8b0235aa98f8c26bf94d308be3fdd24154572,6702c7da86d8cdb88d0fc57166286e115ffeb8c0)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[c4d8b0235aa98f8c26bf94d308be3fdd24154572,36bf17bb90cdf7a623499b624b05acde4d2feef5)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[c4d8b0235aa98f8c26bf94d308be3fdd24154572,9333cc809f0a89e001b814155a6cb8903a6274df)"}}], "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": "3.10"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,3.10)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,5.15.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.1.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.6.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.12.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.18.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,7.2.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,*]"}}], "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": "2026-09-16T14:45:05.849128+00:00", "updated": "2026-09-20T05:30:16.741494+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-119"]}