CVE-2026-40685
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-684 |
| Vendor | exim |
| Product | exim |
| Published | Apr 30, 2026 |
| Last Updated | Apr 30, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High
Affected Versions
Exim / Exim
0 < 4.99.2
References
exim.org: https://exim.org/static/doc/security/CVE-2025-40685.txt openwall.com: https://www.openwall.com/lists/oss-security/2026/04/30/21 exim.org: https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40685.assessment code.exim.org: https://code.exim.org/exim/exim/commit/9fdc057e71b87c87a0d3d2288b2810a0efaaba57