{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47254", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-04-10T18:59:19.539Z", "datePublished": "2024-05-21T14:19:49.475Z", "dateUpdated": "2026-08-05T08:46:59.624Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:46:59.624Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngfs2: Fix use-after-free in gfs2_glock_shrink_scan\n\nThe GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() to\nremove the glock from the lru list in __gfs2_glock_put().\n\nOn the shrink scan path, the same flag is cleared under lru_lock but because\nof cond_resched_lock(&lru_lock) in gfs2_dispose_glock_lru(), progress on the\nput side can be made without deleting the glock from the lru list.\n\nKeep GLF_LRU across the race window opened by cond_resched_lock(&lru_lock) to\nensure correct behavior on both sides - clear GLF_LRU after list_del under\nlru_lock." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable path is the local GFS2 glock LRU shrinker and glock put path, reached via local filesystem operations and memory reclaim on a mounted GFS2 volume, not via network packet processing.\nAC:L - An attacker can induce both sides of the race by churning inode/iopen/flock glocks onto the LRU through ordinary file operations while concurrently creating memory pressure to force gfs2_glock_shrink_scan and dispose.\nPR:L - On a multi-user GFS2 deployment the filesystem is already mounted; an unprivileged local user with access to that mount can trigger glock get/put and reclaim without CAP_SYS_ADMIN.\nUI:N - No separate victim action is required; the attacker triggers the race through their own filesystem activity and memory allocation once GFS2 is available.\nS:U - This is a standard in-kernel use-after-free enabling privilege escalation within the same host security authority, not a VM/IOMMU/sandbox boundary crossing.\nC:H - Use-after-free of a slab-allocated gfs2_glock (aspace) object allows reclaim of attacker-controlled contents and arbitrary kernel memory disclosure primitives.\nI:H - The same UAF enables heap spraying and corruption of the freed glock object, providing arbitrary write / control-flow hijacking potential in the kernel.\nA:H - The bug manifests as a kernel use-after-free during list_del in gfs2_dispose_glock_lru (observed under KASAN), which can oops/panic and deny service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/gfs2/glock.c" ], "versions": [ { "version": "6948c6bc17d666663a84c124b3176039e64a58f4", "lessThan": "38ce329534500bf4ae71f81df6a37a406cf187b4", "status": "affected", "versionType": "git" }, { "version": "b568ed385a18c0ddbe41862b69088b636550a04f", "lessThan": "92869945cc5b78ee8a1ef90336fe070893e3458a", "status": "affected", "versionType": "git" }, { "version": "762bb3528249604bc680a9df635e8995740176de", "lessThan": "0364742decb0f02bc183404868b82896f7992595", "status": "affected", "versionType": "git" }, { "version": "bac8520892812dada1ac93f27d96317470d24b1f", "lessThan": "094bf5670e762afa243d2c41a5c4ab71c7447bf4", "status": "affected", "versionType": "git" }, { "version": "7881ef3f33bb80f459ea6020d1e021fc524a6348", "lessThan": "86fd5b27db743a0ce0cc245e3a34813b2aa6ec1d", "status": "affected", "versionType": "git" }, { "version": "7881ef3f33bb80f459ea6020d1e021fc524a6348", "lessThan": "a61156314b66456ab6a291ed5deba1ebd002ab3c", "status": "affected", "versionType": "git" }, { "version": "7881ef3f33bb80f459ea6020d1e021fc524a6348", "lessThan": "e87ef30fe73e7e10d2c85bdcc778dcec24dca553", "status": "affected", "versionType": "git" }, { "version": "7881ef3f33bb80f459ea6020d1e021fc524a6348", "lessThan": "1ab19c5de4c537ec0d9b21020395a5b5a6c059b2", "status": "affected", "versionType": "git" }, { "version": "1e7a416fb765c9072479dc424780c0937ba99270", "status": "affected", "versionType": "git" }, { "version": "dcbdbe13796ffa561510d2686a6318564e728bbd", "status": "affected", "versionType": "git" }, { "version": "4.4.181", "lessThan": "4.4.274", "status": "affected", "versionType": "semver" }, { "version": "4.9.180", "lessThan": "4.9.274", "status": "affected", "versionType": "semver" }, { "version": "4.14.123", "lessThan": "4.14.238", "status": "affected", "versionType": "semver" }, { "version": "4.19.47", "lessThan": "4.19.196", "status": "affected", "versionType": "semver" }, { "version": "5.0.20", "lessThan": "5.1", "status": "affected", "versionType": "semver" }, { "version": "5.1.6", "lessThan": "5.2", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/gfs2/glock.c" ], "versions": [ { "version": "5.2", "status": "affected" }, { "version": "0", "lessThan": "5.2", "status": "unaffected", "versionType": "semver" }, { "version": "4.4.274", "lessThanOrEqual": "4.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.9.274", "lessThanOrEqual": "4.9.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.238", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.196", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.127", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.45", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.12.12", "lessThanOrEqual": "5.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.13", "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": "4.4.181", "versionEndExcluding": "4.4.274" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9.180", "versionEndExcluding": "4.9.274" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14.123", "versionEndExcluding": "4.14.238" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.47", "versionEndExcluding": "4.19.196" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.2", "versionEndExcluding": "5.4.127" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.2", "versionEndExcluding": "5.10.45" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.2", "versionEndExcluding": "5.12.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.2", "versionEndExcluding": "5.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0.20" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1.6" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/38ce329534500bf4ae71f81df6a37a406cf187b4" }, { "url": "https://git.kernel.org/stable/c/92869945cc5b78ee8a1ef90336fe070893e3458a" }, { "url": "https://git.kernel.org/stable/c/0364742decb0f02bc183404868b82896f7992595" }, { "url": "https://git.kernel.org/stable/c/094bf5670e762afa243d2c41a5c4ab71c7447bf4" }, { "url": "https://git.kernel.org/stable/c/86fd5b27db743a0ce0cc245e3a34813b2aa6ec1d" }, { "url": "https://git.kernel.org/stable/c/a61156314b66456ab6a291ed5deba1ebd002ab3c" }, { "url": "https://git.kernel.org/stable/c/e87ef30fe73e7e10d2c85bdcc778dcec24dca553" }, { "url": "https://git.kernel.org/stable/c/1ab19c5de4c537ec0d9b21020395a5b5a6c059b2" } ], "title": "gfs2: Fix use-after-free in gfs2_glock_shrink_scan", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2024-06-17T17:37:55.520472Z", "id": "CVE-2021-47254", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { 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