Use-After-Free in Exim with GnuTLS TLS Configuration

Publication date: 2026-09-19

Last updated on: 2026-09-19

Assigner: MITRE

Description

Exim before 4.100.1, when certain non-default TLS settings are used with GnuTLS, has a use-after-free.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-09-19

Last Modified

2026-09-19

Generated

2026-09-20

AI Q&A

2026-09-20

EPSS Evaluated

N/A

NVD

CVE-2026-94055

Affected Vendors & Products

Vendor	Product	Version / Range
exim	exim	to 4.100.1 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-416	The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

Executive Summary

Exim before version 4.100.1 has a use-after-free vulnerability when specific non-default TLS settings are used with GnuTLS. This means the software may incorrectly access memory after it has been freed, potentially leading to crashes or other unexpected behavior.

Impact Analysis

This vulnerability could cause Exim to crash or behave unpredictably, potentially disrupting email services. It may also allow attackers to execute arbitrary code or cause denial-of-service conditions if exploited.

Mitigation Strategies

Upgrade Exim to version 4.100.1 or later to address the use-after-free vulnerability in TLS handling with GnuTLS.

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