CVE-2026-12413
HighCVSS 7.5Summary
An invalidly formatted IKEv2 fragment causes the Libreswan pluto daemon to crash and restart due to an off-by-one error in the PASSERT assertion. Continued exploitation leads to denial of service. IKEv1 is not affected.
Risk Assessment
The organization is vulnerable to a Denial of Service (DoS) attack by sending specially crafted IKEv2 packets. Repeated attacks can cause continuous daemon restarts and VPN service disruption.
Recommendation
Immediately update Libreswan to a patched version. As a temporary workaround, disable IKEv2 fragmentation (fragmentation=no) in connection configuration until the update is applied.
Original NVD description (English source)
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.