CVE-2025-39950Public exploit

Local kernel crash via unchecked NULL skb

Published Oct 4, 2025 · Updated Oct 4, 2025

NULL pointer dereference in Linux 6.7 through 6.12.48 and 6.13 through 6.16.8 allows local users to crash the kernel. tcp_ao_finish_connect() receives a NULL skb during connect() and reads tcp_hdr(skb)->seq without first validating the pointer. Triggering the crash requires a TCP socket with a TCP-AO key and TCP_REPAIR enabled; the demonstrated result is a kernel oops and service interruption.

CVSS severity5.5
Medium
EPSS probability0.15%
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 Linux 6.7 through 6.12.48 and 6.13 through 6.16.8 allows local users to crash the kernel. tcp_ao_finish_connect() receives a NULL skb during connect() and reads tcp_hdr(skb)->seq without first validating the pointer. Triggering the crash requires a TCP socket with a TCP-AO key and TCP_REPAIR enabled; the demonstrated result is a kernel oops and service interruption.

The record

CVE
CVE-2025-39950
Published
Oct 4, 2025
Updated
Oct 4, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=6.7
  2. Affected versionversion=7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f <2e7bba08923ebc675b1f0e0e0959e68e53047838
  3. Affected versionversion=7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f <5f445eb259906b61a518487a790e11d07d31738c
  4. Affected versionversion=7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f <993b734d31ab804747ac961b1ee664b023c3b5fa

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.7; version=7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f <2e7bba08923ebc675b1f0e0e0959e68e53047838; version=7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f <5f445eb259906b61a518487a790e11d07d31738c; version=7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f <993b734d31ab804747ac961b1ee664b023c3b5fa

Published CVSS scores

5.5CanonicalCVSS: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 exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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