CVE-2026-40686: Exim

Medium severity, CVSS 5.3. EPSS: 0.4% chance of exploitation in the next 30 days.

In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.

Affected products

• Exim Exim: before 4.99.2 (fixed in 4.99.2)

Published 2026-04-30. Last modified 2026-06-17.