CVE-2026-77206

NameCVE-2026-77206
DescriptionLibreswan's IKEv2 state machine has a null pointer dereference bug in the EAP handling code for authentication. As a result of inconsistency within the IKEv2 state machine code, this bug can be triggered by any IKEv2 connection, even if EAP is not configured at all. The error is caused by a fall-through where it incorrectly dereferences ike->sa.st_eap which is NULL. A malicious IKE_AUTH packet can trigger this bug, meaning the peer does not need to be authenticated. The bug results in a crash and restart of the pluto daemon. No remote code execution is possible. Continued exploitation can cause a denial of service.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1150899

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libreswan (PTS)bookworm4.10-2+deb12u1vulnerable
trixie5.2-2.2vulnerable
forky, sid5.2-2.5vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libreswansource(unstable)(unfixed)1150899

Notes

https://libreswan.org/security/CVE-2026-77206/CVE-2026-77206.txt
https://libreswan.org/security/CVE-2026-77206/

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