CVE-2026-64119

CPU denial of service via RCU list race

Published Jul 19, 2026 · Updated Jul 19, 2026

Denial of service in the Linux Kernel L2TP subsystem allows local users to pin a host CPU indefinitely through concurrent session commands. l2tp_session_unhash() uses list_del_init() on an RCU-walked session list, leaving self-referential links that trap l2tp_session_get_by_ifname() in an infinite loop. Reachability requires l2tp_core to be loaded and CAP_NET_ADMIN in a network namespace, which an unprivileged local user can obtain through a user-namespace sandbox; the wedged CPU stalls host RCU grace periods and the syscall cannot be killed.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux Kernel L2TP subsystem allows local users to pin a host CPU indefinitely through concurrent session commands. l2tp_session_unhash() uses list_del_init() on an RCU-walked session list, leaving self-referential links that trap l2tp_session_get_by_ifname() in an infinite loop. Reachability requires l2tp_core to be loaded and CAP_NET_ADMIN in a network namespace, which an unprivileged local user can obtain through a user-namespace sandbox; the wedged CPU stalls host RCU grace periods and the syscall cannot be killed.

The record

CVE
CVE-2026-64119
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-835, T1499.004
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=6.11.3 <6.12
  2. Affected versionversion=6.12
  3. Affected versionversion=89b768ec2dfefaeba5212de14fc71368e12d06ba <5e40919a40cb3e590ed45c2a54a4a2518aa88a99
  4. Affected versionversion=89b768ec2dfefaeba5212de14fc71368e12d06ba <979c017803c40829b03acd9e5236e354b7622360
  5. Affected versionversion=89b768ec2dfefaeba5212de14fc71368e12d06ba <acab6314bb75be994f720ed13e9d9139cbf828a8
  6. Affected versionversion=89b768ec2dfefaeba5212de14fc71368e12d06ba <e0c3dd7b30cc5ee42ab502da140cda93d794a20b
  7. Affected versionversion=b3dd82a879f25db9d096ae3053f657aa4260ecc6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.11.3 <6.12; version=6.12; version=89b768ec2dfefaeba5212de14fc71368e12d06ba <5e40919a40cb3e590ed45c2a54a4a2518aa88a99; version=89b768ec2dfefaeba5212de14fc71368e12d06ba <979c017803c40829b03acd9e5236e354b7622360; version=89b768ec2dfefaeba5212de14fc71368e12d06ba <acab6314bb75be994f720ed13e9d9139cbf828a8; version=89b768ec2dfefaeba5212de14fc71368e12d06ba <e0c3dd7b30cc5ee42ab502da140cda93d794a20b; version=b3dd82a879f25db9d096ae3053f657aa4260ecc6

Published CVSS scores

7.0Red HatCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5NVDCVSS: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.

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-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499.004Application or System Exploitation

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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