{"id":"CVE-2026-53391","state":"PUBLISHED","title":"NFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr\n\nnfs4_decode_mp_ds_addr() decodes the r_netid and r_addr opaques of a\nnetaddr4 from a GETDEVICEINFO multipath-DS body, then immediately\ncalls strrchr(buf, '.') to locate the port separator. Both decodes\nuse xdr_stream_decode_string_dup(), and the current code checks only\n\"nlen < 0\" / \"rlen < 0\" before dereferencing the returned string.\n\nWhen the on-wire opaque has length zero, xdr_stream_decode_opaque_inline()\nreturns 0 and xdr_stream_decode_string_dup() falls through to its\n\"*str = NULL; return ret\" tail, leaving buf NULL with a return value\nof 0. The \"< 0\" check does not catch this, and the next line is\nstrrchr(NULL, '.'), a kernel NULL pointer dereference reachable from\nany pNFS-flexfile client mounted against a malicious or compromised\nmetadata server.\n\nReject the zero-length cases explicitly so the decoder fails with\n-EBADMSG (treated as a malformed GETDEVICEINFO body) instead of\npanicking the client.","publishedAt":"2026-07-19T12:01:55.521Z","updatedAt":"2026-10-19T20:07:45.936Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"76b94cbd32aacf36a641956385a852635c6802b9","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"c8e4e0c701d0192a2efb6df059c0f9e19678c23d","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"427ab81a811dab4bca9d19f82eec5847ae42646e","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"012d37a568bfbb2c9686f03ade75560bc7139956","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"30aae62e50b4e074a90a9a5e15246548fbdc1182","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"41fe0f7b84f0cb822ae10ab08592996a592b2a25","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfs/pnfs_nfs.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.0","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_nfs.c"]}],"references":["https://git.kernel.org/stable/c/76b94cbd32aacf36a641956385a852635c6802b9","https://git.kernel.org/stable/c/c8e4e0c701d0192a2efb6df059c0f9e19678c23d","https://git.kernel.org/stable/c/6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea","https://git.kernel.org/stable/c/427ab81a811dab4bca9d19f82eec5847ae42646e","https://git.kernel.org/stable/c/012d37a568bfbb2c9686f03ade75560bc7139956","https://git.kernel.org/stable/c/30aae62e50b4e074a90a9a5e15246548fbdc1182","https://git.kernel.org/stable/c/41fe0f7b84f0cb822ae10ab08592996a592b2a25"],"weaknesses":["CWE-476"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53391.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53391","state":"PUBLISHED","datePublished":"2026-07-19T12:01:55.521Z","dateUpdated":"2026-10-19T20:07:45.936Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-06-09T07:44:35.402Z"},"containers":{"cna":{"title":"NFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr\n\nnfs4_decode_mp_ds_addr() decodes the r_netid and r_addr opaques of a\nnetaddr4 from a GETDEVICEINFO multipath-DS body, then immediately\ncalls strrchr(buf, '.') to locate the port separator. Both decodes\nuse xdr_stream_decode_string_dup(), and the current code checks only\n\"nlen < 0\" / \"rlen < 0\" before dereferencing the returned string.\n\nWhen the on-wire opaque has length zero, xdr_stream_decode_opaque_inline()\nreturns 0 and xdr_stream_decode_string_dup() falls through to its\n\"*str = NULL; return ret\" tail, leaving buf NULL with a return value\nof 0. The \"< 0\" check does not catch this, and the next line is\nstrrchr(NULL, '.'), a kernel NULL pointer dereference reachable from\nany pNFS-flexfile client mounted against a malicious or compromised\nmetadata server.\n\nReject the zero-length cases explicitly so the decoder fails with\n-EBADMSG (treated as a malformed GETDEVICEINFO body) instead of\npanicking the client."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"76b94cbd32aacf36a641956385a852635c6802b9","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"c8e4e0c701d0192a2efb6df059c0f9e19678c23d","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"427ab81a811dab4bca9d19f82eec5847ae42646e","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"012d37a568bfbb2c9686f03ade75560bc7139956","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"30aae62e50b4e074a90a9a5e15246548fbdc1182","versionType":"git"},{"version":"6b7f3cf96364eaf597940cb5c68a682894829915","status":"affected","lessThan":"41fe0f7b84f0cb822ae10ab08592996a592b2a25","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfs/pnfs_nfs.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.0","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_nfs.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/76b94cbd32aacf36a641956385a852635c6802b9"},{"url":"https://git.kernel.org/stable/c/c8e4e0c701d0192a2efb6df059c0f9e19678c23d"},{"url":"https://git.kernel.org/stable/c/6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea"},{"url":"https://git.kernel.org/stable/c/427ab81a811dab4bca9d19f82eec5847ae42646e"},{"url":"https://git.kernel.org/stable/c/012d37a568bfbb2c9686f03ade75560bc7139956"},{"url":"https://git.kernel.org/stable/c/30aae62e50b4e074a90a9a5e15246548fbdc1182"},{"url":"https://git.kernel.org/stable/c/41fe0f7b84f0cb822ae10ab08592996a592b2a25"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The crash is triggered by processing a malicious GETDEVICEINFO RPC response from an NFS metadata server over the network, on the standard NFSv4 client path used by pNFS file and flexfile layouts.\nAC:L - Once a victim is a pNFS client, the attacker reliably triggers the bug by sending a GETDEVICEINFO body with a zero-length r_netid or r_addr opaque; no race or special memory layout is required.\nPR:N - The attacker acts as (or compromises) the remote NFS metadata server and needs no local privileges on the victim client; exploitation is delivered entirely through NFS protocol responses to an already-established mount.\nUI:N - In the highest-impact scenario—a compromised enterprise/HPC metadata server or autofs-managed pNFS mount—no further victim action is needed beyond normal file I/O that provokes GETDEVICEINFO.\nS:U - The vulnerability causes a kernel panic on the NFS client itself and does not cross a security boundary such as a VM escape or sandbox breakout.\nC:N - This is a NULL pointer dereference in strrchr() with no out-of-bounds read or use-after-free; it does not disclose kernel memory or attacker-controlled data.\nI:N - There is no memory corruption, arbitrary write, or control-flow hijack primitive—only an immediate NULL dereference that terminates kernel execution.\nA:H - The NULL pointer dereference in kernel context causes an oops or panic, fully denying availability of the affected client (and any co-hosted workloads until reboot)."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:50:42.650Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"5.15.211"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.1.177"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.6.144"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.12.95"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.18.38"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"7.1.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-53391","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:30:09.630598Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-476","lang":"en","type":"CWE","description":"CWE-476 NULL Pointer Dereference"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:07:45.936Z"}}]}}}