{"id":"CVE-2026-97554","state":"PUBLISHED","title":"smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr()\n\ncifs_posix_to_fattr() ignores the return value of posix_info_parse().\nWhen a malformed POSIX directory entry is encountered (e.g. invalid\nSID lengths from an untrusted server), posix_info_parse() returns -1\nwithout populating the 'parsed' struct.  The uninitialized stack\nmemory in parsed.owner and parsed.group is then passed to\nsid_to_id(), which processes the garbage bytes and passes them to\nrequest_key() to construct a SID string, potentially leaking kernel\nstack contents to the userspace idmap daemon.\n\nFix this by checking the return value and skipping the SID-to-id\nmapping when parsing fails.  The remaining fattr fields (timestamps,\nmode, etc.) are populated directly from the 'info' pointer so they\nare unaffected.","publishedAt":"2026-09-25T10:21:45.851Z","updatedAt":"2026-10-30T12:37:18.935Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"1915b69e36906968e2b698699d0f219875ae846e","versionType":"git"},{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"604feb3e8141bf11f5afd48d36d401fee5af9536","versionType":"git"},{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"33106019c3be57b5fc6411cfaad6d98214a51265","versionType":"git"},{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"2be31f252ade791b84f7164991f14436aed1d4b9","versionType":"git"},{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"c9a8b60ce140a68d172452f418137fc7ddbae7db","versionType":"git"},{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"da6e25842431982d5a53cf00d925b98c690f4467","versionType":"git"},{"version":"dd80b98bdf0a4b3206739f3513b0518f27a7b4ef","status":"affected","versionType":"git"},{"version":"d8e39c11f66125f49de55537a6efc8ecadf4a0f7","status":"affected","versionType":"git"},{"version":"5.8.17","status":"affected","lessThan":"5.9","versionType":"semver"},{"version":"5.9.2","status":"affected","lessThan":"5.10","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/readdir.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.10","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/readdir.c"]}],"references":["https://git.kernel.org/stable/c/1915b69e36906968e2b698699d0f219875ae846e","https://git.kernel.org/stable/c/604feb3e8141bf11f5afd48d36d401fee5af9536","https://git.kernel.org/stable/c/33106019c3be57b5fc6411cfaad6d98214a51265","https://git.kernel.org/stable/c/2be31f252ade791b84f7164991f14436aed1d4b9","https://git.kernel.org/stable/c/c9a8b60ce140a68d172452f418137fc7ddbae7db","https://git.kernel.org/stable/c/da6e25842431982d5a53cf00d925b98c690f4467"],"weaknesses":[],"ingestedAt":"2026-10-30T12:56:04.490Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/97xxx/CVE-2026-97554.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-97554","state":"PUBLISHED","datePublished":"2026-09-25T10:21:45.851Z","dateUpdated":"2026-10-30T12:37:18.935Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-24T16:01:01.154Z"},"containers":{"cna":{"title":"smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr()\n\ncifs_posix_to_fattr() ignores the return value of posix_info_parse().\nWhen a malformed POSIX directory entry is encountered (e.g. invalid\nSID lengths from an untrusted server), posix_info_parse() returns -1\nwithout populating the 'parsed' struct.  The uninitialized stack\nmemory in parsed.owner and parsed.group is then passed to\nsid_to_id(), which processes the garbage bytes and passes them to\nrequest_key() to construct a SID string, potentially leaking kernel\nstack contents to the userspace idmap daemon.\n\nFix this by checking the return value and skipping the SID-to-id\nmapping when parsing fails.  The remaining fattr fields (timestamps,\nmode, etc.) are populated directly from the 'info' pointer so they\nare unaffected."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"1915b69e36906968e2b698699d0f219875ae846e","versionType":"git"},{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"604feb3e8141bf11f5afd48d36d401fee5af9536","versionType":"git"},{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"33106019c3be57b5fc6411cfaad6d98214a51265","versionType":"git"},{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"2be31f252ade791b84f7164991f14436aed1d4b9","versionType":"git"},{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"c9a8b60ce140a68d172452f418137fc7ddbae7db","versionType":"git"},{"version":"9934430e2178d5164eb1ac91a9b092f9e7e64745","status":"affected","lessThan":"da6e25842431982d5a53cf00d925b98c690f4467","versionType":"git"},{"version":"dd80b98bdf0a4b3206739f3513b0518f27a7b4ef","status":"affected","versionType":"git"},{"version":"d8e39c11f66125f49de55537a6efc8ecadf4a0f7","status":"affected","versionType":"git"},{"version":"5.8.17","status":"affected","lessThan":"5.9","versionType":"semver"},{"version":"5.9.2","status":"affected","lessThan":"5.10","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/readdir.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.10","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/readdir.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/1915b69e36906968e2b698699d0f219875ae846e"},{"url":"https://git.kernel.org/stable/c/604feb3e8141bf11f5afd48d36d401fee5af9536"},{"url":"https://git.kernel.org/stable/c/33106019c3be57b5fc6411cfaad6d98214a51265"},{"url":"https://git.kernel.org/stable/c/2be31f252ade791b84f7164991f14436aed1d4b9"},{"url":"https://git.kernel.org/stable/c/c9a8b60ce140a68d172452f418137fc7ddbae7db"},{"url":"https://git.kernel.org/stable/c/da6e25842431982d5a53cf00d925b98c690f4467"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:37:18.935Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"7.2.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.8.17"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}