Vulnerability · Published Jul 2, 2026 · Assigned by libreswan
CVE-2026-12413IKEv2 Denial of Service via malformed fragmentation
High 7.5
In plain English
A high-severity security flaw in libreswan from The Libreswan Project. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | libreswan | 5.3.2-1.el10_2 | ALSA-2026:46398 |
| AlmaLinux:8 | libreswan | 4.12-2.el8_10.6 | ALSA-2026:46396 |
| AlmaLinux:9 | libreswan | 4.15-10.el9_8 | ALSA-2026:46397 |
| AlmaLinux:10 | libreswan-minimal | 5.3.2-1.el10_2 | ALSA-2026:46398 |
| Alpine:v3.23 | libreswan | 5.3.3-r0 | ALPINE-CVE-2026-12413 |
| Alpine:v3.24 | libreswan | 5.3.2-r0 | ALPINE-CVE-2026-12413 |
| Debian:12 | libreswan | no fix listed | DEBIAN-CVE-2026-12413 |
| Debian:13 | libreswan | no fix listed | DEBIAN-CVE-2026-12413 |
| Rocky Linux:10 | libreswan | 0:5.3.2-1.el10_2 | RLSA-2026:46398 |
| Rocky Linux:8 | libreswan | 0:4.12-2.el8_10.6 | RLSA-2026:46396 |
| Rocky Linux:9 | libreswan | 0:4.15-10.el9_8 | RLSA-2026:46397 |
| Ubuntu:22.04:LTS | libreswan | no fix listed | UBUNTU-CVE-2026-12413 |
| Ubuntu:24.04:LTS | libreswan | no fix listed | UBUNTU-CVE-2026-12413 |
| Ubuntu:25.10 | libreswan | no fix listed | UBUNTU-CVE-2026-12413 |
| Ubuntu:26.04:LTS | libreswan | no fix listed | UBUNTU-CVE-2026-12413 |
| Ubuntu:26.10 | libreswan | no fix listed | UBUNTU-CVE-2026-12413 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| The Libreswan Project | libreswan | 4.6 – through 5.3 |
Weakness: CWE-193, CWE-617 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H