CVE-2026-77206
IKEv2 pre-authentication Null Pointer Dereference in EAP code
HIGH 7.5
At a glance
- Source
- NVD
- EPSS
- EPSS 0.66 % · percentile 51 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- libreswan
- NVD status
- Awaiting Analysis
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.
Weaknesses (CWE)
- CWE-476 — NULL Pointer Dereference
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | libreswan |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · d42dc95b-23f1-4e06-9076-20753a0fb0df (Secondary) |
European references
- ENISA EUVD · EUVD-2026-100748
- GCVE · GCVE-0-2026-77206
Affected products
| Product | Versions |
|---|---|
| The Libreswan Project · libreswan | affected 4.7 ≤ 5.3.2 ; affected 5.4 ≤ 5.4 ; unaffected 5.3.3 ; unaffected 5.4.1 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |