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Vulnerabilities

Vulnerability · CVE-2026-77206

Libreswan's IKEv2 state machine has a null pointer dereference bug in the EAP handling code for authentication.

Published Oct 13, 2026 · catalog updated Oct 13, 2026 · Libreswan's IKEv2 state machine

Check if you run it

No confirmed exploitation is on record for CVE-2026-77206. EPSS is 0.52%. Act only if a listed version of Libreswan's IKEv2 state machine is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Libreswan's IKEv2 state machine).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.52%
Remediation
Advisory link
Affected products
See sources for product scope

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.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-77206

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-77206. EPSS is 0.52%. Act only if a listed version of Libreswan's IKEv2 state machine is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-476: NULL Pointer Dereference. EPSS 0.52%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 13, 2026 · Catalog

    Detected

    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

Sources

  • CVE.orgVulnerability recordCVE-2026-77206

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-77206

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-77206

    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

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.