CVE-2026-53262

High

In the Linux kernel, the following vulnerability has been resolved: l2tp: pppol2tp: hold reference to session in pppol2tp_ioctl() pppol2tp_ioctl() read sock->sk->sk_user_data directly without any locks or reference counting. If a controllable sleep was induced during copy_from_user() (e.g. via a userfaultfd page fault sleep), a concurrent socket close could trigger pppol2tp_session_close() asynchronously. This frees the l2tp_session structure via the l2tp_session_del_work workqueue. Upon resuming, the ioctl thread dereferences the stale session pointer, resulting in a Use-After-Free (UAF). Fix this by securely fetching the session reference using the RCU-safe, refcounted helper pppol2tp_sock_to_session(sk) on entry. This locks the session's refcount across the sleep. We structured the function to exit via standard err breaks, guaranteeing that l2tp_session_put() is cleanly called on all return paths to drop the reference. To preserve existing behavior we validate the session and its magic signature only for the specific L2TP commands that require it. This ensures that generic/unknown ioctls called on an unconnected socket still return -ENOIOCTLCMD and correctly fall back to generic handlers (e.g. in sock_do_ioctl()).

Package Linux Kernel
Published 2026-06-25
Last modified 2026-07-08
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 2.6.35 and later are affected. Fixed in 6.12.94, 6.18.36, 7.0.13, 7.1 and their respective stable series.

Affected from
≥ 2.6.35
Fixed in
✓ 6.12.94 6.12.x ✓ 6.18.36 6.18.x ✓ 7.0.13 7.0.x ✓ 7.1

References

4 total

Frequently asked questions

  • What is CVE-2026-53262?

    CVE-2026-53262 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 2.6.35 onward and has been patched in 6.12.94, 6.18.36, 7.0.13 and others. CVE-2026-53262 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-53262?

    CVE-2026-53262 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-53262?

    Yes. CVE-2026-53262 has been patched. Fixed versions include 6.12.94, 6.18.36, 7.0.13 and others. If you are running Linux kernel 2.6.35 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-53262 actively exploited?

    No. CVE-2026-53262 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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