{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74350", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.886Z", "datePublished": "2026-08-15T05:58:37.298Z", "dateUpdated": "2026-10-15T10:08:58.167Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-15T10:08:58.167Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: validate fast symlink target during inode read\n\nocfs2_validate_inode_block() already rejects several inconsistent\nself-contained dinodes before they are exposed to the rest of the\nfilesystem. Fast symlinks need the same treatment.\n\nA zero-cluster symlink is treated as a fast symlink and later read through\npage_get_link() and ocfs2_fast_symlink_read_folio(). That path uses\nstrnlen() on the inline payload and then copies len + 1 bytes into the\nfolio. If a corrupt dinode stores an i_size that does not fit the inline\narea or omits the terminating NUL at i_size, that copy reads past the end\nof the inode block buffer.\n\nReject zero-cluster symlink dinodes whose i_size exceeds the inline\nfast-symlink capacity or whose inline payload is not NUL-terminated\nexactly at i_size when the inode block is validated. This keeps malformed\nfast symlinks from reaching the read path.\n\nValidation reproduced this kernel report:\nKASAN use-after-free in ocfs2_fast_symlink_read_folio+0x12c/0x1f0\nRIP: 0033:0x7f5c6d859aa7\nRead of size 3905\nCall trace:\n dump_stack_lvl+0x66/0xa0 (?:?)\n print_report+0xce/0x630 (?:?)\n ocfs2_fast_symlink_read_folio+0x12c/0x1f0 (fs/ocfs2/inode.c:?)\n srso_alias_return_thunk+0x5/0xfbef5 (?:?)\n __virt_addr_valid+0x19f/0x330 (?:?)\n kasan_report+0xe0/0x110 (?:?)\n kasan_check_range+0x105/0x1b0 (?:?)\n __asan_memcpy+0x23/0x60 (?:?)\n filemap_read_folio+0x27/0xe0 (?:?)\n filemap_read_folio+0x35/0xe0 (?:?)\n do_read_cache_folio+0x138/0x230 (?:?)\n __page_get_link+0x26/0x110 (?:?)\n page_get_link+0x2e/0x70 (?:?)\n vfs_readlink+0x15e/0x250 (?:?)\n touch_atime+0x4d/0x370 (?:?)\n do_readlinkat+0x186/0x200 (?:?)\n do_user_addr_fault+0x65a/0x890 (?:?)\n __x64_sys_readlink+0x46/0x60 (?:?)\n do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)\n entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)" } ], "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 - OCFS2 cluster nodes commonly NFS-export shared LUNs; nfsd READLINK reaches vfs_readlink→page_get_link→ocfs2_fast_symlink_read_folio on a forged zero-cluster symlink dinode on the volume, giving a remote network attack path without a local syscall.\nAC:L - A forged dinode fully controls i_size and inline bytes; strnlen() bounded only by ocfs2_fast_symlink_chars() then memcpy_to_folio() copies len+1 past the inode buffer_head (KASAN read ~3905), deterministically and without races.\nPR:N - Triggering needs only permission to read the symlink: a remote NFS client on an exported share, or any unprivileged local/cluster user; planting the malformed dinode uses attacker-controlled on-disk metadata on shared storage, not init-namespace root on the victim.\nUI:N - Once the corrupt fast symlink exists on a mounted/exported volume, readlink(2), NFS READLINK, or path lookup via get_link automatically pulls the inline target through ocfs2_fast_symlink_read_folio with no further deliberate victim action.\nS:U - Impact stays within the host kernel parsing the OCFS2 symlink (memory disclosure/crash/privilege escalation on the server); no VM escape, IOMMU bypass, or cross-authority scope change.\nC:H - memcpy_to_folio() performs an out-of-bounds read up to ~3900 bytes past the inode block buffer (KASAN UAF/slab read of size 3905); OOB/UAF kernel reads enable arbitrary adjacent-heap disclosure.\nI:H - The same unvalidated strnlen/memcpy path corrupts kernel memory semantics (KASAN UAF) and, per kernel CNA guidance, UAF/OOB reads adjacent slab objects can be leveraged into write/control-flow primitives via heap grooming.\nA:H - KASAN reports use-after-free in ocfs2_fast_symlink_read_folio during the over-wide memcpy; such kernel memory faults typically oops/panic the host, fully denying availability." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/ocfs2/inode.c" ], "versions": [ { "version": "ea022dfb3c2a4680483b00eb2fecc9fc4f6091d1", "lessThan": "d94bf50756d7f80bb728ad58246376649e1035b6", "status": "affected", "versionType": "git" }, { "version": "ea022dfb3c2a4680483b00eb2fecc9fc4f6091d1", "lessThan": "f9e2cb692b77a679b1f4cc2b7b277fa908586533", "status": "affected", "versionType": "git" }, { "version": "ea022dfb3c2a4680483b00eb2fecc9fc4f6091d1", "lessThan": "e234973f286ed2e8961a24561ec91594ec3e3ff8", "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/ocfs2/inode.c" ], "versions": [ { "version": "3.5", "status": "affected" }, { "version": "0", "lessThan": "3.5", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "3.5", "versionEndExcluding": "6.18.57" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.5", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.5", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d94bf50756d7f80bb728ad58246376649e1035b6" }, { "url": "https://git.kernel.org/stable/c/f9e2cb692b77a679b1f4cc2b7b277fa908586533" }, { "url": "https://git.kernel.org/stable/c/e234973f286ed2e8961a24561ec91594ec3e3ff8" } ], "title": "ocfs2: validate fast symlink target during inode read", "x_generator": { "engine": "bippy-1.2.0" } } } }