VulnerabilityPublished 25 Sep 2026Updated 19 Oct 2026

CVE-2026-97564: Linux kernel · smb: client: reject userspace cifs.idmap descriptions

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:41 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a, e5964064e3fbe6325893408faff08ca33de0e2c3, d9d7eeb0cea5b55b82888f443622fd8d4ee064f3 +3

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 4d79dba0e00749fa40de8ef13a9b85ce57a1603b, < f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a	Fixed in f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a
LinuxLinux	Affected ≥ 4d79dba0e00749fa40de8ef13a9b85ce57a1603b, < e5964064e3fbe6325893408faff08ca33de0e2c3	Fixed in e5964064e3fbe6325893408faff08ca33de0e2c3
LinuxLinux	Affected ≥ 4d79dba0e00749fa40de8ef13a9b85ce57a1603b, < d9d7eeb0cea5b55b82888f443622fd8d4ee064f3	Fixed in d9d7eeb0cea5b55b82888f443622fd8d4ee064f3
LinuxLinux	Affected ≥ 4d79dba0e00749fa40de8ef13a9b85ce57a1603b, < 96751028c0d4dec785709ea3eb0ab38a4f2ded96	Fixed in 96751028c0d4dec785709ea3eb0ab38a4f2ded96
LinuxLinux	Affected ≥ 4d79dba0e00749fa40de8ef13a9b85ce57a1603b, < 17c93bcd17755523c21abb22cbf2a41a6eb0caaf	Fixed in 17c93bcd17755523c21abb22cbf2a41a6eb0caaf
LinuxLinux	Affected ≥ 4d79dba0e00749fa40de8ef13a9b85ce57a1603b, < 1d3b24b16a0b013792e8f1e3ed060f0b46f537d1	Fixed in 1d3b24b16a0b013792e8f1e3ed060f0b46f537d1

AI-suggested

A fix is available and has been applied in the Linux kernel. Users should update to the fixed kernel versions identified by the commits (hashes provided). No additional mitigation is required as the vulnerability is resolved by restricting acceptance of cifs.idmap descriptions to kernel-originated requests only.

Description

A vulnerability in the Linux kernel's SMB client allows untrusted userspace to supply cifs.idmap key descriptions with authority-bearing fields that are improperly trusted by the kernel. This could lead to privilege escalation by allowing crafted keys to be processed in root context. The issue is fixed by restricting acceptance of cifs.idmap descriptions only to those requested using the kernel's private root credentials.

Impact

The vulnerability allows untrusted userspace to supply crafted cifs.idmap key descriptions containing authority-bearing fields that the kernel mistakenly trusts as originating from the kernel. This can lead to privilege escalation by enabling unauthorized manipulation of security identifiers and user/group mappings within the kernel context. However, there is no indication of active exploitation in the wild.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 13:41 UTC

Technical details

References

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