CVE-2026-40685 MEDIUM

CVE-2026-40685

Vendor Exim
Product Exim
Weakness CWE-684
Published April 30, 2026
Last update May 1, 2026
View on NVD All CVEs

CVSS base score

6.5/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality None
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

What the vulnerability does

01Description

In Exim before 4.99.2, when JSON lookup is enabled, an out-of-bounds heap write can occur when a JSON operator encounters malformed JSON in an untrusted header, because of an incorrect implementation of \ skipping.

Key dates

02Disclosure timeline

April 30, 2026 CVE published
May 1, 2026 Record updated