CVE-2026-46243Public exploit

Local privilege escalation via forged cifs.spnego descriptions

Published Jun 1, 2026 · Updated Jun 1, 2026

Improper input validation in the Linux kernel CIFS client allows local users to gain elevated privileges through forged cifs.spnego keys. The cifs.spnego key parser accepts userspace-created descriptions carrying pid, uid, creduid, and upcall_target as though CIFS generated them under its private spnego_cred. Exploitation requires local low-privileged access, CIFS with cifs.upcall, and user namespaces; a forged request can drive privileged helper behavior.

CVSS severity7.1
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in the Linux kernel CIFS client allows local users to gain elevated privileges through forged cifs.spnego keys. The cifs.spnego key parser accepts userspace-created descriptions carrying pid, uid, creduid, and upcall_target as though CIFS generated them under its private spnego_cred. Exploitation requires local low-privileged access, CIFS with cifs.upcall, and user namespaces; a forged request can drive privileged helper behavior.

The record

CVE
CVE-2026-46243
Published
Jun 1, 2026
Updated
Jun 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-20, CWE-825, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.6.24
  2. Affected versionversion=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <0aece6685fc80a8de492688ca2315fb86ec379c7
  3. Affected versionversion=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <2035acfb17221729b1b8ac335e941868a04ca079
  4. Affected versionversion=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <3da1fdf4efbc490041eb4f836bf596201203f8f2
  5. Affected versionversion=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <7713bd320ed4fc3d08a227cd8e41242219a16981
  6. Affected versionversion=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <91f89c1d83e80417629791fcef6af8140d7d01c8
  7. Affected versionversion=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <9544559e59438a4b609b2fdfa0763d8360572824
  8. Affected versionversion=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <a3bbda6502a9398b816fa2e71c9a3f955f58013d
  9. Affected versionversion=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <cf20038657d6d4974349556a34e08fe0490bebbc

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.24; version=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <0aece6685fc80a8de492688ca2315fb86ec379c7; version=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <2035acfb17221729b1b8ac335e941868a04ca079; version=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <3da1fdf4efbc490041eb4f836bf596201203f8f2; version=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <7713bd320ed4fc3d08a227cd8e41242219a16981; version=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <91f89c1d83e80417629791fcef6af8140d7d01c8; version=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <9544559e59438a4b609b2fdfa0763d8360572824; version=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <a3bbda6502a9398b816fa2e71c9a3f955f58013d; version=f1d662a7d5e5322e583aad6b3cfec03d8f27b435 <cf20038657d6d4974349556a34e08fe0490bebbc

Published CVSS scores

7.1kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
7.8CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-825Expired Pointer Dereference
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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