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TI-2023-29325 Aliases CVE-2023-53020GHSA-7fmf-h6vh-qp27

l2tp: close all race conditions in l2tp_tunnel_register()

Priority LOW 21CWE-362Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 3 fixed, 3 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: l2tp: close all race conditions in l2tp_tunnel_register() The code in l2tp_tunnel_register() is racy in several ways: 1. It modifies the tunnel socket _after_ publishing it. 2. It calls setup_udp_tunnel_sock() on an existing socket without locking. 3. It changes sock lock class on fly, which triggers many syzbot reports. This patch amends all of them by moving socket initialization code before publishing and under sock lock. As suggested by Jakub, the l2tp lockdep class is not necessary as we can just switch to bh_lock_sock_nested().

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00141 3rd percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.166, 5.15.91, 6.1.9 +1Red Hat: 1 advisoryRed Hat: 3 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux3.6 and later5.10.166, 5.15.91, 6.1.9, 6.2Patch availableCNA
  • Linux VendorLinux Affected 3.6 and later Fixed in 5.10.166, 5.15.91, 6.1.9, 6.2 Patch available CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*3.6 to before 5.10.166; 5.11 to before 5.15.91; 5.16 to before 6.1.9VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.2:rc1:*:*:*:*:*:*6.2 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.2:rc2:*:*:*:*:*:*6.2 rc2VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.2:rc3:*:*:*:*:*:*6.2 rc3VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.2:rc4:*:*:*:*:*:*6.2 rc4VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 3.6 to before 5.10.166; 5.11 to before 5.15.91; 5.16 to before 6.1.9 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.2:rc1:*:*:*:*:*:* Versions 6.2 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.2:rc2:*:*:*:*:*:* Versions 6.2 rc2 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.2:rc3:*:*:*:*:*:* Versions 6.2 rc3 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.2:rc4:*:*:*:*:*:* Versions 6.2 rc4 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.166, 5.15.91, 6.1.9, 6.2

Red Hat 1 advisory

  • RHSA-2023:2458 Released 2023-05-09 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-284.11.1.el9_2, kernel-64k-debug-devel-matched-5.14.0-284.11.1.el9_2, kernel-64k-devel-5.14.0-284.11.1.el9_2 +10
    • Red Hat Enterprise Linux BaseOS (v. 9) bpftool-7.0.0-284.11.1.el9_2, kernel-5.14.0-284.11.1.el9_2, kernel-64k-5.14.0-284.11.1.el9_2 +29
    • Red Hat Enterprise Linux CRB (v. 9) kernel-tools-libs-devel-5.14.0-284.11.1.el9_2

Vendor assessments

Red Hat

Red Hat rating: Low. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 8AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2023:2458
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2023:2458
Red Hat Enterprise Linux CRB (v. 9)Fixed RHSA-2023:2458
Not affected: 2 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-53020
  2. 2026-10-03 Alias added: GHSA-7fmf-h6vh-qp27

References

Patch 4

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences