CVE-2026-80638

{"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"}}}}

{}

{"affected": [{"affectedData": [{"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"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "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."}], "id": "CVE-2026-80638", "lastModified": "2026-08-29T07:16:47.790", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-28T08:16:48.720", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1ec3cca2d8b6b9ff6584ca626d4c8918bbf48d44"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f5255516ec7add3a6d5d37853ad5a9a9ddb14305"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent", "id": "2525464", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2525464"}, "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-787", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent\n[BUG]\nUnlinking a refcounted file whose refcount tree has leaf blocks\ntriggers a fortify panic due to an out-of-bounds write.\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[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.", "A flaw was found in the ocfs2 component of the Linux kernel. When a user unlinks a refcounted file whose refcount tree has leaf blocks, an out-of-bounds write occurs within the ocfs2_remove_refcount_extent() function. This happens because a memset operation writes past the intended memory boundary due to an incorrect size calculation. A successful exploit of this vulnerability can lead to a system crash, resulting in a denial of service (DoS)."], "name": "CVE-2026-80638", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "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": "Not affected", "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"}], "public_date": "2026-08-28T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-80638\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-80638\nhttps://lore.kernel.org/linux-cve-announce/2026082840-CVE-2026-80638-fbf1@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[2f26f58df041bbcf692730ff4d8ab0f250d9670d,f5255516ec7add3a6d5d37853ad5a9a9ddb14305)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[2f26f58df041bbcf692730ff4d8ab0f250d9670d,1ec3cca2d8b6b9ff6584ca626d4c8918bbf48d44)"}}], "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": "6.19"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.19)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.5,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2,*]"}}], "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": "2026-08-28T09:30:18.290259+00:00", "updated": "2026-09-02T05:30:08.152179+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}