CVE-2026-40685

—

CVSS 3.1

9.8 critical

EPSS

<1%p25

Published

Apr 30, 2026 (Apr 30, 2026)

Modified

Jun 17, 2026

Description

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.

Vendors: exim
Products: exim
Weakness: CWE-684, CWE-787
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

NVD CVE.org GitHub PoCs EPSS (0.3%)

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