{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64057","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T07:54:57.030Z","datePublished":"2026-07-19T15:39:38.321Z","dateUpdated":"2026-08-05T12:38:46.858Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:38:46.858Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Fix the locking used by afs_get_link()\n\nThe afs filesystem in the kernel doesn't do locking correctly for symbolic\nlinks.  There are a number of problems:\n\n (1) It doesn't do any locking around afs_read_single() to prevent races\n     between multiple ->get_link() calls, thereby allowing the possibility\n     of leaks.\n\n (2) It doesn't use RCU barriering when accessing the buffer pointers\n     during RCU pathwalk.\n\n (3) It can race with another thread updating the contents of the symlink\n     if a third party updated it on the server.\n\nFix this by the following means:\n\n (0) Move symlink handling into its own file as this makes it more\n     complicated.\n\n (1) Take the validate_lock around afs_read_single() to prevent races\n     between multiple ->get_link() calls.\n\n (2) Keep a separate copy of the symlink contents with an rcu_head.  This\n     is always going to be a lot smaller than a page, so it can be\n     kmalloc'd and save quite a bit of memory.  It also needs a refcount\n     for non-RCU pathwalk.\n\n (3) Split the symlink read and write-to-cache routines in afs from those\n     for directories.\n\n (4) Discard the I/O buffer as soon as the write-to-cache completes as this\n     is a full page (plus a folio_queue).\n\n (5) If there's no cache, discard the I/O buffer immediately after reading\n     and copying if there is no cache."}],"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 flaw is in the AFS client VFS `->get_link` handler reached only via local syscalls (path resolution, `readlink`, and AFS automount), not from in-kernel network protocol handlers processing remote packets.\nAC:L - An attacker can reliably trigger the races by spawning concurrent `open`/`readlink`/pathwalk threads against the same AFS symlink, and can also drive server-side invalidation if they have AFS write access to that symlink.\nPR:L - Exploitation requires only normal filesystem access to traverse or read AFS symlinks on an already-mounted volume; it does not require real init-namespace root, only the same permissions any unprivileged AFS user would have.\nUI:N - No victim interaction is required beyond the attacker issuing their own concurrent symlink-access syscalls on paths they can already reach.\nS:U - Impact is confined to kernel memory corruption or disclosure on the AFS client host; it does not cross VM, container, or IOMMU security boundaries.\nC:H - Missing RCU protection and absent locking around symlink buffer access allow concurrent invalidation/reallocation to expose stale or freed folio memory during RCU pathwalk and concurrent `afs_read_single()` calls.\nI:H - The unsynchronized buffer races constitute use-after-free class corruption that can be leveraged for heap manipulation and arbitrary kernel writes, not merely a bounded symlink read error.\nA:H - Use-after-free and concurrent invalidation of symlink folio buffers during active `get_link`/`readlink` operations can cause kernel oopses or panics, and the races are repeatable on demand."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/afs/Makefile","fs/afs/dir.c","fs/afs/fsclient.c","fs/afs/inode.c","fs/afs/internal.h","fs/afs/symlink.c","fs/afs/validation.c","fs/afs/yfsclient.c"],"versions":[{"version":"eae9e78951bb02a7b94a9adef6e981413d13c564","lessThan":"77ea917cbed62882a33114b1e23ededb977e4287","status":"affected","versionType":"git"},{"version":"eae9e78951bb02a7b94a9adef6e981413d13c564","lessThan":"c0410adf3da6db46f3513411fcf95e63c2f1d1ad","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/afs/Makefile","fs/afs/dir.c","fs/afs/fsclient.c","fs/afs/inode.c","fs/afs/internal.h","fs/afs/symlink.c","fs/afs/validation.c","fs/afs/yfsclient.c"],"versions":[{"version":"6.14","status":"affected"},{"version":"0","lessThan":"6.14","status":"unaffected","versionType":"semver"},{"version":"7.0.11","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","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":"6.14","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/77ea917cbed62882a33114b1e23ededb977e4287"},{"url":"https://git.kernel.org/stable/c/c0410adf3da6db46f3513411fcf95e63c2f1d1ad"}],"title":"afs: Fix the locking used by afs_get_link()","x_generator":{"engine":"bippy-1.2.0"}}}}