CVE-2026-63918

Local privilege escalation via L2TP refcount race

Published Jul 19, 2026 · Updated Jul 19, 2026

Use-after-free in Linux Kernel L2TP session lookup allows local users to execute kernel code by racing netlink operations. l2tp_session_get_by_ifname uses refcount_inc after an RCU lookup, so concurrent deletion can reduce the session count to zero before the getter returns a pointer later freed by kfree_rcu. The path requires CAP_NET_ADMIN in a network namespace and PREEMPT_RT scheduling; successful exploitation permits kernel-memory disclosure, corruption, code execution, or a crash.

CVSS severity7.8
High
EPSS probability0.16%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux Kernel L2TP session lookup allows local users to execute kernel code by racing netlink operations. l2tp_session_get_by_ifname uses refcount_inc after an RCU lookup, so concurrent deletion can reduce the session count to zero before the getter returns a pointer later freed by kfree_rcu. The path requires CAP_NET_ADMIN in a network namespace and PREEMPT_RT scheduling; successful exploitation permits kernel-memory disclosure, corruption, code execution, or a crash.

The record

CVE
CVE-2026-63918
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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=6.12
  2. Affected versionversion=abe7a1a7d0b69e63b1bca5f9531023a52336784f <05f95729ca844704d15e49ce14868af4b403b32b
  3. Affected versionversion=abe7a1a7d0b69e63b1bca5f9531023a52336784f <782d60a6596aee9b29c2eecfa70033899278bf65
  4. Affected versionversion=abe7a1a7d0b69e63b1bca5f9531023a52336784f <947013fd7c8c35dd5856557b215840098a3f67f8
  5. Affected versionversion=abe7a1a7d0b69e63b1bca5f9531023a52336784f <ee80455feffb9cb62b5b58715cabeff495e666b2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.12; version=abe7a1a7d0b69e63b1bca5f9531023a52336784f <05f95729ca844704d15e49ce14868af4b403b32b; version=abe7a1a7d0b69e63b1bca5f9531023a52336784f <782d60a6596aee9b29c2eecfa70033899278bf65; version=abe7a1a7d0b69e63b1bca5f9531023a52336784f <947013fd7c8c35dd5856557b215840098a3f67f8; version=abe7a1a7d0b69e63b1bca5f9531023a52336784f <ee80455feffb9cb62b5b58715cabeff495e666b2

Published CVSS scores

7.8LinuxCVSS: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 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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