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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Fixed version: Linux Linux 1915b69e36906968e2b698699d0f219875ae846e, 2be31f252ade791b84f7164991f14436aed1d4b9, 33106019c3be57b5fc6411cfaad6d98214a51265; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 1915b69e36906968e2b698699d0f219875ae846e, 2be31f252ade791b84f7164991f14436aed1d4b9, 33106019c3be57b5fc6411cfaad6d98214a51265; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Sep 25, 2026
Updated
Oct 30, 2026
EPSS
0.2% · 11th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • dd80b98bdf0a4b3206739f3513b0518f27a7b4ef, d8e39c11f66125f49de55537a6efc8ecadf4a0f7, 5.10affected
    • 9934430e2178d5164eb1ac91a9b092f9e7e64745 and later · before 1915b69e36906968e2b698699d0f219875ae846eaffected · git
    • 9934430e2178d5164eb1ac91a9b092f9e7e64745 and later · before 604feb3e8141bf11f5afd48d36d401fee5af9536affected · git
    • 9934430e2178d5164eb1ac91a9b092f9e7e64745 and later · before 33106019c3be57b5fc6411cfaad6d98214a51265affected · git
    • 9934430e2178d5164eb1ac91a9b092f9e7e64745 and later · before 2be31f252ade791b84f7164991f14436aed1d4b9affected · git
    • 9934430e2178d5164eb1ac91a9b092f9e7e64745 and later · before c9a8b60ce140a68d172452f418137fc7ddbae7dbaffected · git
    • 9934430e2178d5164eb1ac91a9b092f9e7e64745 and later · before da6e25842431982d5a53cf00d925b98c690f4467affected · git
    • 5.8.17 and later · before 5.9affected · semver
    • 5.9.2 and later · before 5.10affected · semver
    • before 5.10not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:14linuxbefore 7.2.7-17.2.7-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-97552Sep 25, 2026 · xfs: initialise error in xfs_defer_finish_one()
    0Monitor
  • ← EarlierCVE-2026-97553Sep 25, 2026 · xfs: lock the healthmon when inserting unmount event
    0Monitor
  • Later →CVE-2026-97555Sep 25, 2026 · smb: client: fix heap overflow in DACL owner/group rewrite
    35Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux1915b69e36906968e2b698699d0f219875ae846eVendor (CNA)
Linux Linux2be31f252ade791b84f7164991f14436aed1d4b9Vendor (CNA)
Linux Linux33106019c3be57b5fc6411cfaad6d98214a51265Vendor (CNA)
Linux Linux5.10Vendor (CNA)
Linux Linux5.9Vendor (CNA)
Linux Linux604feb3e8141bf11f5afd48d36d401fee5af9536Vendor (CNA)
Linux Linuxc9a8b60ce140a68d172452f418137fc7ddbae7dbVendor (CNA)
Linux Linuxda6e25842431982d5a53cf00d925b98c690f4467Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux7.2.7-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records