CVE-2026-40685

CRITICAL 9.8CVE-2026-40685 · Published 30/04/2026 · updated 17/06/2026

Package	Affected versions	Patched versions
exim exim	`< 4.99.2`	`4.99.2`

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.

References

code.exim.org/exim/exim/commit/9fdc057e71b87c87a0d3d2288b2810a0efaaba57 · Patch
exim.org/static/doc/security/CVE-2026-40685.txt · Broken Link
exim.org/static/doc/security/cve-2026-04.1/CVE2026-40685.assessment · Vendor Advisory
openwall.com/lists/oss-security/2026/04/30/21 · Mailing List

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