Out-of-bounds Write Affecting exim4 package, versions <4.96-15+deb12u9


Severity

Recommended
0.0
critical
0
10

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Threat Intelligence

EPSS
0.32% (24th percentile)

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  • Snyk IDSNYK-ECHOLATEST-EXIM4-18234364
  • published23 Jul 2026
  • disclosed30 Apr 2026

Introduced: 30 Apr 2026

CVE-2026-40685  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade Echo:latest exim4 to version 4.96-15+deb12u9 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream exim4 package and not the exim4 package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1