CVE-2026-97554smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr() cifs_posix_to_fattr() ignores the return value of posix_info_parse(). When a malformed POSIX directory entry is encountered (e.g. invalid SID lengths from an untrusted server), posix_info_parse() returns -1 without populating the 'parsed' struct. The uninitialized stack memory in parsed.owner and parsed.group is then passed to sid_to_id(), which processes the garbage bytes and passes them to request_key() to construct a SID string, potentially leaking kernel stack contents to the userspace idmap daemon. Fix this by checking the return value and skipping the SID-to-id mapping when parsing fails. The remaining fattr fields (timestamps, mode, etc.) are populated directly from the 'info' pointer so they are unaffected.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | 9934430e2178d5164eb1ac91a9b092f9e7e64745 builds before 2be31f252ade791b84f7164991f14436aed1d4b9; from 9934430e2178d5164eb1ac91a9b092f9e7e64745 before c9a8b60ce140a68d172452f418137fc7ddbae7db; from 9934430e2178d5164eb1ac91a9b092f9e7e64745 before da6e25842431982d5a53cf00d925b98c690f4467; dd80b98bdf0a4b3206739f3513b0518f27a7b4ef; d8e39c11f66125f49de55537a6efc8ecadf4a0f7; from 5.8.17 before 5.9; from 5.9.2 before 5.10 | CNA record |
References
- https://git.kernel.org/stable/c/2be31f252ade791b84f7164991f14436aed1d4b9
- https://git.kernel.org/stable/c/c9a8b60ce140a68d172452f418137fc7ddbae7db
- https://git.kernel.org/stable/c/da6e25842431982d5a53cf00d925b98c690f4467
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.