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.
Affected versions
Linux kernel versions
5.8.17,
5.9.2,
5.10
and later are affected. Fixed in
7.2.7,
7.3-rc3
and their respective stable series.
References
2 totalFrequently asked questions
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What is CVE-2026-97554?
CVE-2026-97554 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.8.17 onward and has been patched in 7.2.7 and 7.3-rc3. CVE-2026-97554 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-97554?
Yes. CVE-2026-97554 has been patched. Fixed versions include 7.2.7 and 7.3-rc3. If you are running Linux kernel 5.8.17 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-97554 actively exploited?
No. CVE-2026-97554 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.