Name: CVE-2026-40684: Incorrect Provision of Specified Functionality
Creator: Rapid7
Published: 2026-04-30T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-40684, CWE-684, CVSS 5.9, EPSS 0.00362

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.

CVSS Details

CVSS 3.1 Base Score: 5.9
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Alpine Linux	—	Upgrade exim	May 4, 2026	Apr 30, 2026
Debian	—	Upgrade exim4	May 13, 2026	May 13, 2026
Exim	—	Upgrade Exim to version 4.99.2	Jun 9, 2026	Apr 30, 2026
Gentoo Linux	—	Upgrade mail-mta/exim.	Aug 16, 2026	Aug 14, 2026

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CVSS Details

Covered by Rapid7

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