{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2022-49554", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-02-26T02:08:31.590Z", "datePublished": "2025-02-26T02:14:02.649Z", "dateUpdated": "2026-08-05T08:55:40.785Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:55:40.785Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nzsmalloc: fix races between asynchronous zspage free and page migration\n\nThe asynchronous zspage free worker tries to lock a zspage's entire page\nlist without defending against page migration. Since pages which haven't\nyet been locked can concurrently migrate off the zspage page list while\nlock_zspage() churns away, lock_zspage() can suffer from a few different\nlethal races.\n\nIt can lock a page which no longer belongs to the zspage and unsafely\ndereference page_private(), it can unsafely dereference a torn pointer to\nthe next page (since there's a data race), and it can observe a spurious\nNULL pointer to the next page and thus not lock all of the zspage's pages\n(since a single page migration will reconstruct the entire page list, and\ncreate_page_chain() unconditionally zeroes out each list pointer in the\nprocess).\n\nFix the races by using migrate_read_lock() in lock_zspage() to synchronize\nwith page migration." } ], "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 in mm/zsmalloc.c (async_free_zspage → lock_zspage racing with zs_page_migrate), reached when an unprivileged local process drives zram/zswap alloc/free via swap or compressed-page I/O and concurrent compaction; it is not reachable from the network stack.\nAC:L - A local attacker can drive both sides of the race by allocating/freeing zsmalloc-backed swap objects (zs_free → deferred free) while inducing compaction/migration of those movable zspages, so success does not depend on conditions outside attacker influence.\nPR:L - On common deployments (e.g. Android with zram swap, or zswap with zsmalloc), any unprivileged local user can trigger zs_malloc/zs_free and memory pressure without capabilities or init-namespace root.\nUI:N - Exploitation requires no victim action beyond the system already using zsmalloc-backed zram/zswap; the attacker triggers the race solely through their own memory and I/O activity.\nS:U - Impact stays within the host kernel's authority (local memory corruption / privilege escalation); this is not a VM escape, IOMMU bypass, or other cross-boundary break.\nC:H - The race can lock the wrong page and dereference page_private(), follow a torn page->index pointer, or free a zspage while unlocked pages remain in use—UAF/memory-corruption primitives that enable arbitrary kernel reads.\nI:H - Incomplete locking of the zspage chain while migration rebuilds it via create_page_chain() allows freeing or resetting pages still under migration, yielding heap corruption exploitable for arbitrary writes and control-flow hijacking.\nA:H - The same races produce NULL/invalid pointer dereferences, use-after-free crashes, and kernel oops/panic when page_private or list links are observed inconsistently during free versus migration." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/zsmalloc.c" ], "versions": [ { "version": "77ff465799c60294e248000cd22ae8171da3304c", "lessThan": "3674d8a8dadd03a447dd21069d4dacfc3399b63b", "status": "affected", "versionType": "git" }, { "version": "77ff465799c60294e248000cd22ae8171da3304c", "lessThan": "645996efc2ae391246d595832aaa6f9d3cc338c7", "status": "affected", "versionType": "git" }, { "version": "77ff465799c60294e248000cd22ae8171da3304c", "lessThan": "fc658c083904427abbf8f18280d517ee2668677c", "status": "affected", "versionType": "git" }, { "version": "77ff465799c60294e248000cd22ae8171da3304c", "lessThan": "fae05b2314b147a78fbed1dc4c645d9a66313758", "status": "affected", "versionType": "git" }, { "version": "77ff465799c60294e248000cd22ae8171da3304c", "lessThan": "3ec459c8810e658401be428d3168eacfc380bdd0", "status": "affected", "versionType": "git" }, { "version": "77ff465799c60294e248000cd22ae8171da3304c", "lessThan": "8ba7b7c1dad1f6503c541778f31b33f7f62eb966", "status": "affected", "versionType": "git" }, { "version": "77ff465799c60294e248000cd22ae8171da3304c", "lessThan": "c5402fb5f71f1a725f1e55d9c6799c0c7bec308f", "status": "affected", "versionType": "git" }, { "version": "77ff465799c60294e248000cd22ae8171da3304c", "lessThan": "2505a981114dcb715f8977b8433f7540854851d8", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/zsmalloc.c" ], "versions": [ { "version": "4.14", "status": "affected" }, { "version": "0", "lessThan": "4.14", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.282", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.246", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.197", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.120", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.45", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.17.13", "lessThanOrEqual": "5.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.18.2", "lessThanOrEqual": "5.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.19", "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": "4.14", "versionEndExcluding": "4.14.282" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "4.19.246" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "5.4.197" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "5.10.120" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "5.15.45" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "5.17.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "5.18.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "5.19" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/3674d8a8dadd03a447dd21069d4dacfc3399b63b" }, { "url": "https://git.kernel.org/stable/c/645996efc2ae391246d595832aaa6f9d3cc338c7" }, { "url": "https://git.kernel.org/stable/c/fc658c083904427abbf8f18280d517ee2668677c" }, { "url": "https://git.kernel.org/stable/c/fae05b2314b147a78fbed1dc4c645d9a66313758" }, { "url": "https://git.kernel.org/stable/c/3ec459c8810e658401be428d3168eacfc380bdd0" }, { "url": "https://git.kernel.org/stable/c/8ba7b7c1dad1f6503c541778f31b33f7f62eb966" }, { "url": "https://git.kernel.org/stable/c/c5402fb5f71f1a725f1e55d9c6799c0c7bec308f" }, { "url": "https://git.kernel.org/stable/c/2505a981114dcb715f8977b8433f7540854851d8" } ], "title": "zsmalloc: fix races between asynchronous zspage free and page migration", "x_generator": { "engine": "bippy-1.2.0" } } } }