{"id":"CVE-2026-53391","summary":"NFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr","details":"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 \u003c 0\" / \"rlen \u003c 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 \"\u003c 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.","modified":"2026-07-23T09:59:44.988598287Z","published":"2026-07-19T12:01:55.521Z","related":["openSUSE-SU-2026:11339-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53391.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/012d37a568bfbb2c9686f03ade75560bc7139956"},{"type":"WEB","url":"https://git.kernel.org/stable/c/30aae62e50b4e074a90a9a5e15246548fbdc1182"},{"type":"WEB","url":"https://git.kernel.org/stable/c/41fe0f7b84f0cb822ae10ab08592996a592b2a25"},{"type":"WEB","url":"https://git.kernel.org/stable/c/427ab81a811dab4bca9d19f82eec5847ae42646e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea"},{"type":"WEB","url":"https://git.kernel.org/stable/c/76b94cbd32aacf36a641956385a852635c6802b9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c8e4e0c701d0192a2efb6df059c0f9e19678c23d"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53391.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53391"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6b7f3cf96364eaf597940cb5c68a682894829915"},{"fixed":"76b94cbd32aacf36a641956385a852635c6802b9"},{"fixed":"c8e4e0c701d0192a2efb6df059c0f9e19678c23d"},{"fixed":"6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea"},{"fixed":"427ab81a811dab4bca9d19f82eec5847ae42646e"},{"fixed":"012d37a568bfbb2c9686f03ade75560bc7139956"},{"fixed":"30aae62e50b4e074a90a9a5e15246548fbdc1182"},{"fixed":"41fe0f7b84f0cb822ae10ab08592996a592b2a25"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53391.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.0.0"},{"fixed":"5.15.211"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.177"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.144"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.95"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.38"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53391.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}