CVE-2025-21775

Kernel crash via unchecked NULL CAN frame dereference

Published Feb 27, 2025 · Updated May 11, 2026

NULL pointer dereference in the ctucanfd CAN driver in Linux allows local users to crash the kernel during an error interrupt. When CAN-frame socket-buffer allocation fails, ctucan_err_interrupt() leaves struct can_frame NULL but writes through it in one controller-state branch. Exploitation requires local low-privileged access, an active CTU CAN FD controller, and memory pressure sufficient to fail allocation; the bounded impact is a kernel crash.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the ctucanfd CAN driver in Linux allows local users to crash the kernel during an error interrupt. When CAN-frame socket-buffer allocation fails, ctucan_err_interrupt() leaves struct can_frame NULL but writes through it in one controller-state branch. Exploitation requires local low-privileged access, an active CTU CAN FD controller, and memory pressure sufficient to fail allocation; the bounded impact is a kernel crash.

The record

CVE
CVE-2025-21775
Published
Feb 27, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=2dcb8e8782d8e4c38903bf37b1a24d3ffd193da7 <84b9ac59978a6a4e0812d1c938fad97306272cef
  2. Affected versionversion=2dcb8e8782d8e4c38903bf37b1a24d3ffd193da7 <9bd24927e3eeb85642c7baa3b28be8bea6c2a078
  3. Affected versionversion=2dcb8e8782d8e4c38903bf37b1a24d3ffd193da7 <b0e592dd46a0a952b41c3bf6c963afdd6a42b526
  4. Affected versionversion=2dcb8e8782d8e4c38903bf37b1a24d3ffd193da7 <e505b83b9ee6aa0ae2f4395f573a66579ae403fb
  5. Affected versionversion=2dcb8e8782d8e4c38903bf37b1a24d3ffd193da7 <e7e2e2318b1f085044126ba553a4e619842fc36d
  6. Affected versionversion=5.19

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2dcb8e8782d8e4c38903bf37b1a24d3ffd193da7 <84b9ac59978a6a4e0812d1c938fad97306272cef; version=2dcb8e8782d8e4c38903bf37b1a24d3ffd193da7 <9bd24927e3eeb85642c7baa3b28be8bea6c2a078; version=2dcb8e8782d8e4c38903bf37b1a24d3ffd193da7 <b0e592dd46a0a952b41c3bf6c963afdd6a42b526; version=2dcb8e8782d8e4c38903bf37b1a24d3ffd193da7 <e505b83b9ee6aa0ae2f4395f573a66579ae403fb; version=2dcb8e8782d8e4c38903bf37b1a24d3ffd193da7 <e7e2e2318b1f085044126ba553a4e619842fc36d; version=5.19

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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