Out-of-bounds Write Affecting exim package, versions <4.99.5-r0


Severity

Recommended
0.0
critical
0
10

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Threat Intelligence

EPSS
0.58% (46th percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-EXIM-18968779
  • published20 Aug 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 Chainguard exim to version 4.99.5-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream exim package and not the exim package as distributed by Chainguard. See How to fix? for Chainguard 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