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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-40684 Detail

Description

In Exim before 4.99.2, on systems using musl libc (not glibc), an attacker can crash the connection instance when malformed DNS data is present in PTR records. This is caused by a dn_expand oddity in octal printing.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
http://www.openwall.com/lists/oss-security/2026/05/01/11 CVE
https://code.exim.org/exim/exim/commit/628bbaca7672748d941a12e7cd5f0122a4e18c81 MITRE Patch 
https://exim.org/static/doc/security/CVE-2026-40684.txt MITRE Broken Link 
https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40684.assessment MITRE Vendor Advisory 
https://www.openwall.com/lists/oss-security/2026/04/30/21 MITRE Mailing List  Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-684 Incorrect Provision of Specified Functionality MITRE  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

4 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-40684
NVD Published Date:
04/30/2026
NVD Last Modified:
05/01/2026
Source:
MITRE