VDB-418442 · CVE-2026-77206 · GCVE-0-2026-77206

Libreswan up to 5.3.2/5.4/5.4.0 EAP null pointer dereference

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.3	$0-$5k	1.05-

Summaryinfo

A vulnerability labeled as critical has been found in Libreswan up to 5.3.2/5.4/5.4.0. This affects an unknown part of the component EAP Handler. Such manipulation leads to null pointer dereference. This vulnerability is uniquely identified as CVE-2026-77206. The attack can be launched remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Libreswan up to 5.3.2/5.4/5.4.0 and classified as critical. Affected by this issue is an unknown part of the component EAP Handler. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. CVE summarizes:

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.

The advisory is available at libreswan.org. This vulnerability is handled as CVE-2026-77206 since 08/20/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. The technical details are unknown and an exploit is not available.

Upgrading to version 5.3.3 or 5.4.1 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

Libreswan

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.3

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (libreswan): 🔒

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Libreswan 5.3.3/5.4.1

Timelineinfo

08/20/2026 CVE reserved
10/13/2026 +54 days VulDB entry created
10/14/2026 +0 days Advisory disclosed
10/14/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: libreswan.org
Status: Confirmed

CVE: CVE-2026-77206 (🔒)
GCVE (CVE): GCVE-0-2026-77206
GCVE (VulDB): GCVE-100-418442

Entryinfo

Created: 10/14/2026 00:11
Changes: 10/14/2026 00:11 (62)
Complete: 🔍
Cache ID: 216::103