{"id":"CVE-2026-63800","state":"PUBLISHED","title":"pNFS: Fix use-after-free in pnfs_update_layout()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\npNFS: Fix use-after-free in pnfs_update_layout()\n\nWhen hitting the NFS_LAYOUT_RETURN branch in pnfs_update_layout(),\nthe code calls pnfs_prepare_to_retry_layoutget(lo). If it succeeds,\npnfs_put_layout_hdr(lo) is called before trace_pnfs_update_layout(),\nwhich still references 'lo'. This results in a use-after-free when the\ntracepoint accesses lo's fields.\n\nFix this by moving the tracepoint call before pnfs_put_layout_hdr(lo).","publishedAt":"2026-07-19T12:02:06.897Z","updatedAt":"2026-10-19T20:07:47.475Z","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":"06f58dbc49a23c99e5c0f246879ed16667f7bf8f","status":"affected","lessThan":"4ad8b9a85dbf57ca532ee9e65ad7e6498bfbbf98","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"1f24b8302c77dcaf79c64c073877a3b9f4dd25d2","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"9c0fb5c09ae5bd68dc0038692af8127029cb0385","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"7e37e9b3e82ade881e1798e2f4fcc54aff7793c1","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"2883ddd7542b4437a2ab4908fe2773f690e20889","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"200e7637f4d6a1342987045eea72641524f909dc","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"9645aaf689aff57427ece3b9fa47d5b5399417f4","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"13e198a90ca4050f4bee8a3f23680389a6563ccc","versionType":"git"},{"version":"aa2399f55eff4ec78330bb6fe55f9df53e5cae0c","status":"affected","versionType":"git"},{"version":"5.10.9","status":"affected","lessThan":"5.10.260","versionType":"semver"},{"version":"5.4.91","status":"affected","lessThan":"5.5","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfs/pnfs.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.11","versionType":"semver"},{"version":"5.10.260","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.211","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.177","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.144","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.95","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.38","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.3","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfs/pnfs.c"]}],"references":["https://git.kernel.org/stable/c/4ad8b9a85dbf57ca532ee9e65ad7e6498bfbbf98","https://git.kernel.org/stable/c/1f24b8302c77dcaf79c64c073877a3b9f4dd25d2","https://git.kernel.org/stable/c/9c0fb5c09ae5bd68dc0038692af8127029cb0385","https://git.kernel.org/stable/c/7e37e9b3e82ade881e1798e2f4fcc54aff7793c1","https://git.kernel.org/stable/c/2883ddd7542b4437a2ab4908fe2773f690e20889","https://git.kernel.org/stable/c/200e7637f4d6a1342987045eea72641524f909dc","https://git.kernel.org/stable/c/9645aaf689aff57427ece3b9fa47d5b5399417f4","https://git.kernel.org/stable/c/13e198a90ca4050f4bee8a3f23680389a6563ccc"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/63xxx/CVE-2026-63800.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63800","state":"PUBLISHED","datePublished":"2026-07-19T12:02:06.897Z","dateUpdated":"2026-10-19T20:07:47.475Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T07:54:57.013Z"},"containers":{"cna":{"title":"pNFS: Fix use-after-free in pnfs_update_layout()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\npNFS: Fix use-after-free in pnfs_update_layout()\n\nWhen hitting the NFS_LAYOUT_RETURN branch in pnfs_update_layout(),\nthe code calls pnfs_prepare_to_retry_layoutget(lo). If it succeeds,\npnfs_put_layout_hdr(lo) is called before trace_pnfs_update_layout(),\nwhich still references 'lo'. This results in a use-after-free when the\ntracepoint accesses lo's fields.\n\nFix this by moving the tracepoint call before pnfs_put_layout_hdr(lo)."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"06f58dbc49a23c99e5c0f246879ed16667f7bf8f","status":"affected","lessThan":"4ad8b9a85dbf57ca532ee9e65ad7e6498bfbbf98","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"1f24b8302c77dcaf79c64c073877a3b9f4dd25d2","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"9c0fb5c09ae5bd68dc0038692af8127029cb0385","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"7e37e9b3e82ade881e1798e2f4fcc54aff7793c1","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"2883ddd7542b4437a2ab4908fe2773f690e20889","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"200e7637f4d6a1342987045eea72641524f909dc","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"9645aaf689aff57427ece3b9fa47d5b5399417f4","versionType":"git"},{"version":"2c8d5fc37fe2384a9bdb6965443ab9224d46f704","status":"affected","lessThan":"13e198a90ca4050f4bee8a3f23680389a6563ccc","versionType":"git"},{"version":"aa2399f55eff4ec78330bb6fe55f9df53e5cae0c","status":"affected","versionType":"git"},{"version":"5.10.9","status":"affected","lessThan":"5.10.260","versionType":"semver"},{"version":"5.4.91","status":"affected","lessThan":"5.5","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfs/pnfs.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.11","versionType":"semver"},{"version":"5.10.260","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.211","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.177","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.144","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.95","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.38","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.3","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfs/pnfs.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/4ad8b9a85dbf57ca532ee9e65ad7e6498bfbbf98"},{"url":"https://git.kernel.org/stable/c/1f24b8302c77dcaf79c64c073877a3b9f4dd25d2"},{"url":"https://git.kernel.org/stable/c/9c0fb5c09ae5bd68dc0038692af8127029cb0385"},{"url":"https://git.kernel.org/stable/c/7e37e9b3e82ade881e1798e2f4fcc54aff7793c1"},{"url":"https://git.kernel.org/stable/c/2883ddd7542b4437a2ab4908fe2773f690e20889"},{"url":"https://git.kernel.org/stable/c/200e7637f4d6a1342987045eea72641524f909dc"},{"url":"https://git.kernel.org/stable/c/9645aaf689aff57427ece3b9fa47d5b5399417f4"},{"url":"https://git.kernel.org/stable/c/13e198a90ca4050f4bee8a3f23680389a6563ccc"}],"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 - A compromised or malicious pNFS NFSv4.1+ metadata server can send CB_LAYOUTRECALL callbacks over the NFSv4 backchannel to force NFS_LAYOUT_RETURN while client file I/O reaches pnfs_update_layout(), exploiting the client from the network in typical enterprise/HPC pNFS deployments.\nAC:L - The attacker controls both sides of the race by issuing layout recalls from the server and driving or waiting for concurrent read/write I/O on the mounted pNFS share; no conditions beyond attacker influence are required once a pNFS session exists.\nPR:N - Exploitation requires no local privileges on the victim client—a remote NFS server with an established pNFS session can trigger the layoutreturn/retry path while any client process performs permitted file I/O on the mount.\nUI:N - No interactive victim action is needed during exploitation; automated workloads, daemons, or batch jobs performing routine I/O on an existing pNFS mount are sufficient to hit the vulnerable code path.\nS:U - The use-after-free corrupts kernel heap memory within the same kernel security domain and does not cross a VM, container, or IOMMU boundary on its own.\nC:H - The tracepoint reads freed pnfs_layout_hdr fields (plh_stateid seqid and hash) after pnfs_put_layout_hdr() drops the final reference, giving an attacker-controlled use-after-free read primitive over kernel heap memory.\nI:H - Use-after-free on a refcounted kernel layout object enables heap grooming and further memory corruption for arbitrary kernel writes or control-flow hijacking, not merely a bounded fault.\nA:H - Dereferencing a freed pnfs_layout_hdr in kernel context can cause an oops or panic, and use-after-free corruption reliably threatens system availability even when full exploitation is not attempted."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:51:05.578Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.9","versionEndExcluding":"5.10.260"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.15.211"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.1.177"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.6.144"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.12.95"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.18.38"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"7.1.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.91"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-63800","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:30:40.400910Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","type":"CWE","description":"CWE-416 Use After Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:07:47.475Z"}}]}}}