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CVE-2026-97564· NVD / CVE Program· CNA Linux

smb: client: reject userspace cifs.idmap descriptions

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: 0.20% (FIRST EPSS).
  • Fixed version: Linux Linux 17c93bcd17755523c21abb22cbf2a41a6eb0caaf, 1d3b24b16a0b013792e8f1e3ed060f0b46f537d1, 96751028c0d4dec785709ea3eb0ab38a4f2ded96; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 17c93bcd17755523c21abb22cbf2a41a6eb0caaf, 1d3b24b16a0b013792e8f1e3ed060f0b46f537d1, 96751028c0d4dec785709ea3eb0ab38a4f2ded96; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1 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: reject userspace cifs.idmap descriptions cifs.idmap key descriptions carry authority-bearing fields (owner and group SIDs and uid/gid values in "os:"/"gs:"/"oi:"/"gi:" form) that the cifs.idmap upcall helper treats as kernel-originating inputs. Unlike its sibling cifs.spnego, the cifs.idmap key type has no vet_description hook, so userspace can create keys of this type through request_key(2)/add_key(2) and supply those fields without CIFS origin. A request_key(2) call with a non-NULL callout then drives a root usermodehelper upcall (/sbin/request-key -> cifs.idmap) that consumes the unvetted description in root context. Only accept cifs.idmap descriptions while CIFS is using its private root_cred to request the key. id_to_sid()/sid_to_id() already run under override_creds(root_cred), so the kernel-originated path is unaffected. This mirrors commit 3da1fdf4efbc ("smb: client: reject userspace cifs.spnego descriptions"), which applied the same restriction to cifs.spnego.

—No exploit Fix available
Published
Sep 25, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 10th 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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  • Not in KEV: no record of exploitation in the wild
  • 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

    • 3.0affected
    • 4d79dba0e00749fa40de8ef13a9b85ce57a1603b and later · before f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6aaffected · git
    • 4d79dba0e00749fa40de8ef13a9b85ce57a1603b and later · before 17c93bcd17755523c21abb22cbf2a41a6eb0caafaffected · git
    • 4d79dba0e00749fa40de8ef13a9b85ce57a1603b and later · before e5964064e3fbe6325893408faff08ca33de0e2c3affected · git
    • 4d79dba0e00749fa40de8ef13a9b85ce57a1603b and later · before 96751028c0d4dec785709ea3eb0ab38a4f2ded96affected · git
    • 4d79dba0e00749fa40de8ef13a9b85ce57a1603b and later · before 1d3b24b16a0b013792e8f1e3ed060f0b46f537d1affected · git
    • 4d79dba0e00749fa40de8ef13a9b85ce57a1603b and later · before d9d7eeb0cea5b55b82888f443622fd8d4ee064f3affected · git
    • before 3.0not affected · semver
    • 6.1.189 and later · up to and including 6.1.*not affected · semver
    • 6.6.158 and later · up to and including 6.6.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
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-2026-97562Sep 25, 2026 · smb: client: pin DFS superblock in iterator callback
    30Monitor
  • ← EarlierCVE-2026-97563Sep 25, 2026 · smb: client: reject out-of-bounds DataOffset in CIFSSMBRead()
    0Monitor
  • Later →CVE-2026-97565Sep 25, 2026 · smb: client: reject short READ responses in CIFSSMBRead()
    0Monitor

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 Linux17c93bcd17755523c21abb22cbf2a41a6eb0caafVendor (CNA)
Linux Linux1d3b24b16a0b013792e8f1e3ed060f0b46f537d1Vendor (CNA)
Linux Linux96751028c0d4dec785709ea3eb0ab38a4f2ded96Vendor (CNA)
Linux Linuxd9d7eeb0cea5b55b82888f443622fd8d4ee064f3Vendor (CNA)
Linux Linuxe5964064e3fbe6325893408faff08ca33de0e2c3Vendor (CNA)
Linux Linuxf29c1ec0e7d8c887a91df3f93bb4617c0ac95c6aVendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.06.6.158.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package 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