{"id":"CVE-2026-64216","state":"PUBLISHED","title":"netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()\n\nnetfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it\nis wanting to unlock and compares that to rreq->no_unlock_folio so that it\ndoesn't unlock a folio being read for netfs_perform_write() or\nnetfs_write_begin().\n\nHowever, given that netfs_unlock_abandoned_read_pages() is called _after_\nNETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to\ndereference is the one specified by ->no_unlock_folio as ownership\nimmediately reverts to the caller.\n\nFix this by storing the folio pointer instead and using that rather than\nthe index.  Also fix netfs_unlock_read_folio() where the same applies.","publishedAt":"2026-07-24T15:23:04.673Z","updatedAt":"2026-08-27T12:39:42.119Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ee4cdf7ba857a894ad1650d6ab77669cbbfa329e","status":"affected","lessThan":"d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c","versionType":"git"},{"version":"ee4cdf7ba857a894ad1650d6ab77669cbbfa329e","status":"affected","lessThan":"6080fa3ecfbb4448a3b47368629534c09b6ec750","versionType":"git"},{"version":"ee4cdf7ba857a894ad1650d6ab77669cbbfa329e","status":"affected","lessThan":"3866d015f33aeedf81338dd99154703bef33faef","versionType":"git"},{"version":"ee4cdf7ba857a894ad1650d6ab77669cbbfa329e","status":"affected","lessThan":"dbe556972100fabb8e5a1b3d2163831ff07b1e8e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/buffered_read.c","fs/netfs/read_collect.c","fs/netfs/read_retry.c","include/linux/netfs.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.106","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.34","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/buffered_read.c","fs/netfs/read_collect.c","fs/netfs/read_retry.c","include/linux/netfs.h"]}],"references":["https://git.kernel.org/stable/c/d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c","https://git.kernel.org/stable/c/6080fa3ecfbb4448a3b47368629534c09b6ec750","https://git.kernel.org/stable/c/3866d015f33aeedf81338dd99154703bef33faef","https://git.kernel.org/stable/c/dbe556972100fabb8e5a1b3d2163831ff07b1e8e"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64216.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64216","state":"PUBLISHED","datePublished":"2026-07-24T15:23:04.673Z","dateUpdated":"2026-08-27T12:39:42.119Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.770Z"},"containers":{"cna":{"title":"netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()\n\nnetfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it\nis wanting to unlock and compares that to rreq->no_unlock_folio so that it\ndoesn't unlock a folio being read for netfs_perform_write() or\nnetfs_write_begin().\n\nHowever, given that netfs_unlock_abandoned_read_pages() is called _after_\nNETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to\ndereference is the one specified by ->no_unlock_folio as ownership\nimmediately reverts to the caller.\n\nFix this by storing the folio pointer instead and using that rather than\nthe index.  Also fix netfs_unlock_read_folio() where the same applies."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ee4cdf7ba857a894ad1650d6ab77669cbbfa329e","status":"affected","lessThan":"d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c","versionType":"git"},{"version":"ee4cdf7ba857a894ad1650d6ab77669cbbfa329e","status":"affected","lessThan":"6080fa3ecfbb4448a3b47368629534c09b6ec750","versionType":"git"},{"version":"ee4cdf7ba857a894ad1650d6ab77669cbbfa329e","status":"affected","lessThan":"3866d015f33aeedf81338dd99154703bef33faef","versionType":"git"},{"version":"ee4cdf7ba857a894ad1650d6ab77669cbbfa329e","status":"affected","lessThan":"dbe556972100fabb8e5a1b3d2163831ff07b1e8e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/buffered_read.c","fs/netfs/read_collect.c","fs/netfs/read_retry.c","include/linux/netfs.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.106","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.34","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/netfs/buffered_read.c","fs/netfs/read_collect.c","fs/netfs/read_retry.c","include/linux/netfs.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c"},{"url":"https://git.kernel.org/stable/c/6080fa3ecfbb4448a3b47368629534c09b6ec750"},{"url":"https://git.kernel.org/stable/c/3866d015f33aeedf81338dd99154703bef33faef"},{"url":"https://git.kernel.org/stable/c/dbe556972100fabb8e5a1b3d2163831ff07b1e8e"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable read-for-write completion is used by network filesystem clients including Ceph, SMB, 9P, and AFS. A malicious filesystem peer can induce failed or malformed reads and control completion timing.\nAC:L - Partial buffered writes and concurrent invalidation can repeatedly trigger the race, with an adjacent bug reproducing approximately 30% of repeated attempts. The attacker can influence completion, reuse, and retry timing.\nPR:N - A malicious filesystem server requires no privileges on the victim client; mount and session credentials belong to the victim.\nUI:N - Once the network filesystem is mounted, ordinary or automated writes can exercise the vulnerable path without further human action.\nS:U - The UAF corrupts resources within the host kernel's existing security authority and does not inherently cross a VM, IOMMU, or sandbox boundary.\nC:H - The stale folio can be freed and reused, and premature unlocking of a replacement page can expose page-cache or kernel contents.\nI:H - If the folio is reused, folio_unlock() can toggle PG_locked on an unrelated page, enabling concurrent memory corruption and potentially code execution.\nA:H - The condition can trigger a VM_BUG_ON_FOLIO kernel crash; incorrect PG_locked state can also cause permanent page-lock waits and system hangs."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-27T12:39:42.119Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.12.106"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.18.34"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}