CVE-2026-43374

Kernel memory corruption via premature percpu free

Published May 8, 2026 · Updated May 8, 2026

Use-after-free in the Linux Kernel nexthop subsystem allows local users to corrupt kernel memory by racing nexthop-group deletion. remove_nh_grp_entry() publishes a replacement group through RCU but frees the removed entry's percpu statistics before the caller's synchronize_net() grace period, leaving preexisting readers to dereference freed memory. The freeing path requires CAP_NET_ADMIN in the active network namespace and concurrent route lookups; a successful race exposes or alters kernel memory or crashes the system.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux Kernel nexthop subsystem allows local users to corrupt kernel memory by racing nexthop-group deletion. remove_nh_grp_entry() publishes a replacement group through RCU but frees the removed entry's percpu statistics before the caller's synchronize_net() grace period, leaving preexisting readers to dereference freed memory. The freeing path requires CAP_NET_ADMIN in the active network namespace and concurrent route lookups; a successful race exposes or alters kernel memory or crashes the system.

The record

CVE
CVE-2026-43374
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 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=6.9
  2. Affected versionversion=f4676ea74b8549cd88dbfe2a592ce4530039e61f <9e08ad731862b22a87cc55f752e16d66cdc9e231
  3. Affected versionversion=f4676ea74b8549cd88dbfe2a592ce4530039e61f <ab5ebab9664214ba41a7633cb4e72f128204f924
  4. Affected versionversion=f4676ea74b8549cd88dbfe2a592ce4530039e61f <abf4feaee6405f1441929c6ebe7a250f2cd170a7
  5. Affected versionversion=f4676ea74b8549cd88dbfe2a592ce4530039e61f <b2662e7593e94ae09b1cf7ee5f09160a3612bcb2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.9; version=f4676ea74b8549cd88dbfe2a592ce4530039e61f <9e08ad731862b22a87cc55f752e16d66cdc9e231; version=f4676ea74b8549cd88dbfe2a592ce4530039e61f <ab5ebab9664214ba41a7633cb4e72f128204f924; version=f4676ea74b8549cd88dbfe2a592ce4530039e61f <abf4feaee6405f1441929c6ebe7a250f2cd170a7; version=f4676ea74b8549cd88dbfe2a592ce4530039e61f <b2662e7593e94ae09b1cf7ee5f09160a3612bcb2

Published CVSS scores

7.8Linux CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.3UbuntuCVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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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