smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr() (CVE-2026-97554) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-97554

smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr()

Answer in brief

CVE-2026-97554 records a Unknown severity vulnerability in smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 25, 2026Updated Sep 25, 2026Source checked Sep 25, 2026First seen by HOL Sep 25, 2026Material review Sep 25, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c9a8b60ce140a68d172452f418137fc7ddbae7db \|\| >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <da6e25842431982d5a53cf00d925b98c690f4467 \|\| >=0 <7.2.7	c9a8b60ce140a68d172452f418137fc7ddbae7db, da6e25842431982d5a53cf00d925b98c690f4467, 7.2.7

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux.
Review the reported fix. Update Linux/Linux to c9a8b60ce140a68d172452f418137fc7ddbae7db if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 25, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.