{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80638","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-26T14:34:25.777Z","datePublished":"2026-08-28T06:48:51.439Z","dateUpdated":"2026-08-29T06:21:38.111Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-29T06:21:38.111Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent\n\n[BUG]\nUnlinking a refcounted file whose refcount tree has leaf blocks\ntriggers a fortify panic due to an out-of-bounds write.\n\n[CAUSE]\nWhen the last leaf block is removed from a refcount tree,\nocfs2_remove_refcount_extent() converts the root back to leaf mode\nwith a bulk memset on &rb->rf_records. rf_records sits in an anonymous\nunion with rf_list. rf_list.l_tree_depth aliases rf_records.rl_count,\nand is 0 for a single-level tree. With rl_count equal to 0, the memset\nwrites past the 16-byte declared size of rf_records, which the fortify\nchecker catches.\n\n[FIX]\nReplace the bulk memset on &rb->rf_records with a correctly-bounded\nmemset on rl_recs[] alone, after setting rl_count to the correct value."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - OCFS2 registers NFS export operations and is commonly NFS-exported on shared cluster storage; remote NFS SETATTR/truncate or REMOVE/unlink on refcounted files reaches ocfs2_decrease_refcount() and the vulnerable memset via kernel nfsd.\nAC:L - An attacker can deterministically create refcounted files with multi-block refcount trees via reflink/copy_file_range, then trigger removal of the last leaf through truncate or unlink; syzbot reproduced this reliably without races or victim-specific timing.\nPR:L - Only normal filesystem write permission on the target file or parent directory is required to truncate/unlink refcounted data; no real-root or init-namespace capabilities are needed beyond access to the mounted OCFS2 volume.\nUI:N - Exploitation requires only attacker-initiated filesystem operations (reflink setup, truncate, or unlink) on objects they can write; no additional end-user or administrator interaction beyond routine file access is needed.\nS:U - Impact is confined to kernel/filesystem integrity and availability on systems running OCFS2; it does not cross a VM, container, or IOMMU security boundary into another authority domain.\nC:H - The out-of-bounds memset corrupts refcount-tree metadata within the on-disk block image, which can misdirect subsequent metadata reads and expose stale or cross-file cluster data on shared cluster filesystems.\nI:H - This is an out-of-bounds write (FORTIFY reported a 384-byte write past a 16-byte declared rf_records object) that zeros arbitrary portions of the refcount root block, corrupting filesystem metadata and enabling further memory corruption primitives.\nA:H - The fortify-detected out-of-bounds write triggers a kernel WARNING/panic during refcount-tree cleanup, causing node crash or denial of service on OCFS2 cluster members processing the malicious truncate or unlink."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ocfs2/refcounttree.c"],"versions":[{"version":"2f26f58df041bbcf692730ff4d8ab0f250d9670d","lessThan":"f5255516ec7add3a6d5d37853ad5a9a9ddb14305","status":"affected","versionType":"git"},{"version":"2f26f58df041bbcf692730ff4d8ab0f250d9670d","lessThan":"1ec3cca2d8b6b9ff6584ca626d4c8918bbf48d44","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/refcounttree.c"],"versions":[{"version":"6.19","status":"affected"},{"version":"0","lessThan":"6.19","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":"6.19","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/f5255516ec7add3a6d5d37853ad5a9a9ddb14305"},{"url":"https://git.kernel.org/stable/c/1ec3cca2d8b6b9ff6584ca626d4c8918bbf48d44"}],"title":"ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent","x_generator":{"engine":"bippy-1.2.0"}}}}