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OpenAdvisories
High · 7.5 Public exploit CVE-2026-12413 EUVD-2026-41439GHSA-vj68-68x2-jwjq

IKEv2 Denial of Service via malformed fragmentation

Published Jul 2, 2026 · Updated Jul 7, 2026 · Assigned by libreswan

Vendor: The Libreswan Project Product: libreswan Package: libreswan Package: libreswan Package: libreswan Package: libreswan Ecosystem: Alpine Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

An invalidly formatted IKEv2 fragment causes the Libreswan pluto daemon to crash and restart. Continued exploitation would cause a denial of service. The function reassemble_v2_incoming_fragments() would ignore unknown outer payloads but still store these in a fixed size array msg_digest.digest[PAYLIMIT]. An off-by-one error in the assertion PASSERT(logger, md->digest_roof < elemsof(md->digest)) causes the daemon to abort. No remote code execution is possible. Any configuration that allows IKEv2 connections that do not set fragmentation=no are vulnerable. IKEv1 is not affected.

Affected products

VendorProductAffectedFixed
The Libreswan Project libreswan 4.6 – ≤ 5.3 5.3.1

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

Debian

Security tracker ↗
ReleasePackageFixed inAdvisory
Debian 13 libreswan No fix yet —
Debian 12 libreswan No fix yet —

Ubuntu

Security tracker ↗
ReleasePackageFixed inAdvisory
Ubuntu 26.10 libreswan No fix yet —
Ubuntu 26.04 LTS libreswan No fix yet —
Ubuntu 25.10 libreswan No fix yet —
Ubuntu 24.04 LTS libreswan No fix yet —
Ubuntu 22.04 LTS libreswan No fix yet —
Show 2 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 20.04 LTS libreswan No fix yet —
Ubuntu 18.04 LTS libreswan No fix yet —

Red Hat

Security tracker ↗
ReleasePackageFixed inAdvisory
RHEL 10 libreswan +1 5.3.2-1.el10_2 RHSA-2026:46398
RHEL 9 libreswan 4.15-10.el9_8 RHSA-2026:46986, RHSA-2026:46397
RHEL 8 libreswan 4.12-2.el8_10.6 RHSA-2026:46396
Show 6 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
RHEL 10.0 EUS libreswan 5.2-1.el10_0.5 RHSA-2026:55449
RHEL 9.6 EUS libreswan 4.15-8.el9_6.1 RHSA-2026:57741
RHEL 9.4 E4S libreswan 4.12-3.el9_4.2 RHSA-2026:61258
RHEL 9.2 E4S libreswan 4.9-5.el9_2.5 RHSA-2026:61779
RHEL 8.8 TUS libreswan 4.9-3.el8_8.3 RHSA-2026:72287
RHEL 8.8 E4S libreswan 4.9-3.el8_8.3 RHSA-2026:72287

AlmaLinux

Errata ↗
ReleasePackageFixed inAdvisory
AlmaLinux 10 libreswan +1 5.3.2-1.el10_2 ALSA-2026:46398
AlmaLinux 9 libreswan 4.15-10.el9_8 ALSA-2026:46397
AlmaLinux 8 libreswan 4.12-2.el8_10.6 ALSA-2026:46396

Rocky Linux

Errata ↗
ReleasePackageFixed inAdvisory
Rocky Linux 10 libreswan 5.3.2-1.el10_2 RLSA-2026:46398
Rocky Linux 9 libreswan 4.15-10.el9_8 RLSA-2026:46397
Rocky Linux 8 libreswan 4.12-2.el8_10.6 RLSA-2026:46396

Alpine

Security tracker ↗
ReleasePackageFixed inAdvisory
Alpine v3.24 libreswan 5.3.2-r0 —
Alpine v3.23 libreswan 5.3.3-r0 —

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 libreswan 4.12-3.amzn2023.0.3 ALAS2023-2026-2039

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 libreswan 4.15-2 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 10 libreswan +1 5.3.2-1.el10_2 ELSA-2026-46398
Oracle Linux 9 libreswan 4.15-10.0.1.el9_8 ELSA-2026-46397
Oracle Linux 8 libreswan 4.12-2.0.1.el8_10.6 ELSA-2026-46396

Public exploits

Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.

Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.

GitHub 1 repository

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

Advisories 21

References