IKEv2 pre-authentication Null Pointer Dereference in EAP code
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.
CVE-2026-77206
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-77206
libreswan
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://github.com/libreswan/libreswan",
"vendor": "The Libreswan Project",
"product": "libreswan",
"versions": [
{
"status": "affected",
"version": "4.7",
"versionType": "semver",
"lessThanOrEqual": "5.3.2"
},
{
"status": "affected",
"version": "5.4",
"versionType": "semver",
"lessThanOrEqual": "5.4"
},
{
"status": "unaffected",
"version": "5.3.3",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.4.1",
"versionType": "semver"
}
],
"packageName": "libreswan",
"collectionURL": "https://github.com/libreswan/libreswan",
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-77206
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #32662 · Revision 1
- Added to Heist Feed
- Publisher date