{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-63827", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-63827", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-07-19T12:02:22.083Z", "updatedAt": "2026-08-17T04:51:35.761Z", "importedAt": "2026-10-24T01:58:20.586Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "apparmor: fix use-after-free in rawdata dedup loop", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\napparmor: fix use-after-free in rawdata dedup loop\n\naa_replace_profiles() walks ns->rawdata_list to dedup the incoming\npolicy blob against entries already attached to existing profiles.\nPer the kernel-doc on struct aa_loaddata, list membership does not\nhold a reference: profiles hold pcount, and when the last pcount\ndrops, do_ploaddata_rmfs() is queued on a workqueue that takes\nns->lock and removes the entry. Between dropping the last pcount\nand the workqueue running, an entry remains on the list with\npcount == 0.\n\naa_get_profile_loaddata() is an unconditional kref_get() on\npcount, so when the dedup loop hits such an entry, refcount\nhardening reports\n\n refcount_t: addition on 0; use-after-free.\n\ninside aa_replace_profiles(), and the poisoned counter then\ntrips \"saturated\" and \"underflow\" warnings on the subsequent\nuses of the same loaddata.\n\nBefore commit a0b7091c4de4 (\"apparmor: fix race on rawdata\ndereference\") the dedup path used a get_unless_zero-style helper\non a single counter, so the existing \"if (tmp)\" guard was\nmeaningful. The split-refcount refactor introduced\naa_get_profile_loaddata(), which has plain kref_get() semantics,\nand the guard quietly became a no-op.\n\nIntroduce aa_get_profile_loaddata_not0(), matching the existing\n_not0 convention used by aa_get_profile_not0(), and use it for\nthe rawdata_list dedup lookup so dying entries are skipped.\n\nReproduced on x86_64 with v7.1-rc5 in QEMU+KVM running Ubuntu\n24.04 + stress-ng 0.17.06:\n\n stress-ng --apparmor 1 --klog-check --timeout 60s\n\nWithout this patch the three refcount_t warnings fire within a\nfew seconds. With it the same 60 s run is clean. Coverage is a\nsmoke-test only; a longer soak with CONFIG_KASAN, CONFIG_KCSAN\nand CONFIG_PROVE_LOCKING would be welcome from anyone with the\ncycles.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "3b8e77c7abab40e6de9ad9de730d77984a498840", "status": "affected", "versionType": "git", "lessThan": "643221da57dbb1a8fd800610331cf1ec27969f71" }, { "version": "d9d8560b9b7932f8cffc4c068c14289220900f79", "status": "affected", "versionType": "git", "lessThan": "b17f0c59cc1525765625cf07d0391b7f9c1ed7e5" }, { "version": "6b6ba87579c7e7c669e0bec91823e7fb693bc5df", "status": "affected", "versionType": "git", "lessThan": "a7a2890028f16e5b0af0bb005d80fcb32559cca3" }, { "version": "6ef1f2926c41ab96952d9696d55a052f1b3a9418", "status": "affected", "versionType": "git", "lessThan": "15fd83a1e42ede15070968806bb6c8b1a5170688" }, { "version": "f9761add6d100962a23996cb68f3d6abdd4d1815", "status": "affected", "versionType": "git", "lessThan": "ce261a20b41db522e320a41bbf1292bf85af66df" }, { "version": "af782cc8871e3683ddd5a3cd2f7df526599863a9", "status": "affected", "versionType": "git", "lessThan": "c3ca2631073b2cef06824fd2bfc452ff7a1023de" }, { "version": "a0b7091c4de45a7325c8780e6934a894f92ac86b", "status": "affected", "versionType": "git", "lessThan": "5e34fa9f6f7cd688ae153fff13139a5cf2d42339" }, { "version": "a0b7091c4de45a7325c8780e6934a894f92ac86b", "status": "affected", "versionType": "git", "lessThan": "6f060496d03e4dc560a40f73770bd08335cb7a27" }, { "version": "763e838adc3c7ec5a7df2990ce84cad951e42721", "status": "affected", "versionType": "git" }, { "version": "5.10.253", "status": "affected", "versionType": "semver", "lessThan": "5.10.261" }, { "version": "5.15.203", "status": "affected", "versionType": "semver", "lessThan": "5.15.212" }, { "version": "6.1.169", "status": "affected", "versionType": "semver", "lessThan": "6.1.177" }, { "version": "6.6.130", "status": "affected", "versionType": "semver", "lessThan": "6.6.144" }, { "version": "6.12.77", "status": "affected", "versionType": "semver", "lessThan": "6.12.95" }, { "version": "6.18.18", "status": "affected", "versionType": "semver", "lessThan": "6.18.38" }, { "version": "6.19.8", "status": "affected", "versionType": "semver", "lessThan": "6.20" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "7.0", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "7.0" }, { "version": "5.10.261", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.212", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.177", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.144", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.95", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.38", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.1.3", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.1.*" }, { "version": "7.2", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }