{"api_version":"1","generated_at":"2026-08-29T12:13:42+00:00","cve":"CVE-2026-80638","urls":{"html":"https://cve.report/CVE-2026-80638","api":"https://cve.report/api/cve/CVE-2026-80638.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80638","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80638"},"summary":{"title":"ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-28 08:16:48","updated_at":"2026-08-29 07:16:47"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"8.8","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.8","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/1ec3cca2d8b6b9ff6584ca626d4c8918bbf48d44","name":"https://git.kernel.org/stable/c/1ec3cca2d8b6b9ff6584ca626d4c8918bbf48d44","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f5255516ec7add3a6d5d37853ad5a9a9ddb14305","name":"https://git.kernel.org/stable/c/f5255516ec7add3a6d5d37853ad5a9a9ddb14305","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80638","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80638","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2f26f58df041bbcf692730ff4d8ab0f250d9670d f5255516ec7add3a6d5d37853ad5a9a9ddb14305 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2f26f58df041bbcf692730ff4d8ab0f250d9670d 1ec3cca2d8b6b9ff6584ca626d4c8918bbf48d44 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.19","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"80638","cve":"CVE-2026-80638","epss":"0.001550000","percentile":"0.049820000","score_date":"2026-08-28","updated_at":"2026-08-29 00:12:17"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/ocfs2/refcounttree.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"f5255516ec7add3a6d5d37853ad5a9a9ddb14305","status":"affected","version":"2f26f58df041bbcf692730ff4d8ab0f250d9670d","versionType":"git"},{"lessThan":"1ec3cca2d8b6b9ff6584ca626d4c8918bbf48d44","status":"affected","version":"2f26f58df041bbcf692730ff4d8ab0f250d9670d","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/ocfs2/refcounttree.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.19"},{"lessThan":"6.19","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"6.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"6.19","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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":{"baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"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."}]}],"providerMetadata":{"dateUpdated":"2026-08-29T06:21:38.111Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"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"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80638","datePublished":"2026-08-28T06:48:51.439Z","dateReserved":"2026-08-26T14:34:25.777Z","dateUpdated":"2026-08-29T06:21:38.111Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-28 08:16:48","lastModifiedDate":"2026-08-29 07:16:47","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80638","Ordinal":"1","Title":"ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent","CVE":"CVE-2026-80638","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80638","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent"}]}}}