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CVE-2026-97554

UnknownEPSS 0.21%

Last modified

CVE-2026-97554 is a vulnerability of currently unknown severity. 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. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

Description

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.

Metrics

EPSS Probability
0.21%

10.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 9934430e2178d5164eb1ac91a9b092f9e7e64745, < 1915b69e36906968e2b698699d0f219875ae846e; >= 9934430e2178d5164eb1ac91a9b092f9e7e64745, < 604feb3e8141bf11f5afd48d36d401fee5af9536; >= 9934430e2178d5164eb1ac91a9b092f9e7e64745, < 33106019c3be57b5fc6411cfaad6d98214a51265; >= 9934430e2178d5164eb1ac91a9b092f9e7e64745, < 2be31f252ade791b84f7164991f14436aed1d4b9; >= 9934430e2178d5164eb1ac91a9b092f9e7e64745, < c9a8b60ce140a68d172452f418137fc7ddbae7db; >= 9934430e2178d5164eb1ac91a9b092f9e7e64745, < da6e25842431982d5a53cf00d925b98c690f4467; dd80b98bdf0a4b3206739f3513b0518f27a7b4ef; d8e39c11f66125f49de55537a6efc8ecadf4a0f7; >= 5.8.17, < 5.9; >= 5.9.2, < 5.10
LinuxLinux5.10

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-97554?
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.
How severe is CVE-2026-97554?
Severity scoring for CVE-2026-97554 is pending analysis. The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-97554?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST