{"id":"CVE-2026-97554","title":"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 direc…","summary":"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 direc…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-908"],"vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c9a8b60ce140a68d172452f418137fc7ddbae7db","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < da6e25842431982d5a53cf00d925b98c690f4467","Linux < 7.2.7","Linux (all versions)"],"published":"2026-09-25","updated":"2026-10-15","sourceUpdated":"2026-10-15T11:18:08.807","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-97554","references":[{"url":"https://git.kernel.org/stable/c/2be31f252ade791b84f7164991f14436aed1d4b9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c9a8b60ce140a68d172452f418137fc7ddbae7db","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/da6e25842431982d5a53cf00d925b98c690f4467","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97554.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-97554"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2541276"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-97554"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97554"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97554.mbox"},{"url":"https://git.kernel.org/stable/c/604feb3e8141bf11f5afd48d36d401fee5af9536"},{"url":"https://git.kernel.org/stable/c/33106019c3be57b5fc6411cfaad6d98214a51265"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00206,"epssPercentile":0.10583,"cvssSource":"vendor","ingestedAt":"2026-09-25T11:06:38.917Z","slug":"CVE-2026-97554","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97554.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":212355,"id":"CVE-2026-97554","ts":1790668156983,"field":"cvss","old":null,"new":"5.5"},{"seq":212354,"id":"CVE-2026-97554","ts":1790668156983,"field":"severity","old":"none","new":"medium"}]}