VDB-360949 · CVE-2026-43859 · Nessus 321070

mutt up to 2.3.1 auth_cram neutralization of null byte

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.
4.3	$0-$5k	0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in mutt up to 2.3.1. The affected element is the function auth_cram. This manipulation causes neutralization of null byte. The identification of this vulnerability is CVE-2026-43859. It is possible to initiate the attack remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in mutt up to 2.3.1 and classified as problematic. Affected by this vulnerability is the function auth_cram. The manipulation with an unknown input leads to a neutralization of null byte vulnerability. The CWE definition for the vulnerability is CWE-158. The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes NUL characters or null bytes when they are sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

mutt before 2.3.2 sometimes uses strfcpy instead of memcpy for the IMAP auth_cram MD5 digest.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-43859 since 05/04/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 321070 (SUSE SLES12 Security Update : mutt (SUSE-SU-2026:2300-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.3.2 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (321070) and CERT Bund (WID-SEC-2026-1343). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

Open Source mutt

Productinfo

Type

Mail Client Software

Name

mutt

Version

License

open-source

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.4
VulDB Meta Temp Score: 4.3

VulDB Base Score: 5.0
VulDB Temp Score: 4.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 3.7
CNA Vector (MITRE): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Neutralization of null byte
CWE: CWE-158 / CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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

Nessus ID: 321070
Nessus Name: SUSE SLES12 Security Update : mutt (SUSE-SU-2026:2300-1)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: mutt 2.3.2

Timelineinfo

05/04/2026 Advisory disclosed
05/04/2026 +0 days CVE reserved
05/04/2026 +0 days VulDB entry created
06/14/2026 +41 days VulDB entry last update

Sourcesinfo

Advisory: 834c5a2ed0479e51e8662a31caed129f136f4805
Status: Confirmed

CVE: CVE-2026-43859 (🔒)
GCVE (CVE): GCVE-0-2026-43859
GCVE (VulDB): GCVE-100-360949
CERT Bund: WID-SEC-2026-1343 - mutt: Mehrere Schwachstellen

Entryinfo

Created: 05/04/2026 09:21
Updated: 06/14/2026 21:39
Changes: 05/04/2026 09:21 (64), 05/04/2026 12:54 (7), 06/14/2026 21:39 (2)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.