Reachable assertion in libreswan - CVE-2026-12413

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Main Vulnerability Database Vulnerabilities #VU135208

Reachable assertion in libreswan - CVE-2026-12413

Published: June 25, 2026


Vulnerability identifier: #VU135208
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-12413
CWE-ID: CWE-617
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to an assertion failure caused by improper bounds checking in reassemble_v2_incoming_fragments() when processing invalidly formatted IKEv2 fragments. A remote attacker can send specially crafted fragmented IKEv2 packets to cause a denial of service.

Only IKEv2 configurations with fragmentation enabled are vulnerable. IKEv1 is not affected.


Affected software

libreswan
Anolis OS
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
openEuler
Red Hat Enterprise Linux Fast Datapath
libreswan (Red Hat package)
libreswan
libreswan-debuginfo
libreswan-help
libreswan-debugsource
libreswan-doc

How to mitigate CVE-2026-12413

Install security update from vendor's website.

libreswan - update to 5.3.1
libreswan (Red Hat package) - addressed in versions 4.12-2.el8_10.6, 4.15-10.el9_8, 5.3.2-1.el9fdp, 5.3.2-1.el10_2
libreswan - addressed in versions 4.12-2.0.2, 5.1-2
libreswan-debuginfo - update to 4.15-3
libreswan-help - update to 4.15-3
libreswan-debugsource - update to 4.15-3
libreswan - update to 4.15-3
libreswan-doc - update to 5.1-2

External References

Related Security Bulletins