All vulnerabilities
CVE-2026-77206

libreswan: IKEv2 pre-authentication Null Pointer Dereference in EAP code

The Libreswan Project libreswan
Open in ThreatlineRecord JSON
CVSS
7.5High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.52%Chance of exploitation activity in the next 30 days, higher than 43% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
Published13 Oct 2026Updated 16 Oct 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

Description

Libreswan'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.

Text from CVE List

Affected versions 4

  • libreswanaffected: 4.7 through 5.3.2CVE List
  • libreswanaffected: 5.4 through 5.4CVE List
  • libreswanunaffected: 5.3.3CVE List
  • libreswanunaffected: 5.4.1CVE List

References 2