CVE-2026-40685
exim4-daemon-heavy: In Exim before 4.99.2, when JSON lookup is enabled, an out-of-bounds heap write can occur when a JSON operator encoun...
CVE-2026-40685 is fixed in 6 products on 1 platform, first by exim4 4.99.1-1ubuntu1.1, released April 29, 2026. It is not reported as exploited. Patch Radar priority: High.
High
CVSS
9.8
Medium
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0032
25th percentile
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| exim4 · Debian 12.15 (bookworm) | 4.96-15+deb12u9 | DEBIAN-CVE-2026-40685 | May 15, 2026 |
| exim4 · Debian 13.5 (trixie) | 4.98.2-1+deb13u2 | DEBIAN-CVE-2026-40685 | May 15, 2026 |
| exim4 · Debian 14 | 4.99.2-1 | DEBIAN-CVE-2026-40685 | May 15, 2026 |
| exim4 · Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | exim4 4.93-13ubuntu1.12+esm1 | Jun 24, 2026 |
| exim4 · Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.7 | exim4 4.95-4ubuntu2.7 | May 15, 2026 |
| exim4 · Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.4 | exim4 4.97-4ubuntu4.4 | May 15, 2026 |
| exim4 · Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.1 | exim4 4.98.2-1ubuntu2.1 | May 15, 2026 |
| exim4 · Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.1 | exim4 4.99.1-1ubuntu1.1 | Apr 29, 2026 |
| exim4-base · Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | exim4-base 4.93-13ubuntu1.12+esm1 | Jun 24, 2026 |
| exim4-base · Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.7 | exim4-base 4.95-4ubuntu2.7 | May 15, 2026 |
| exim4-base · Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.4 | exim4-base 4.97-4ubuntu4.4 | May 15, 2026 |
| exim4-base · Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.1 | exim4-base 4.98.2-1ubuntu2.1 | May 15, 2026 |
| exim4-base · Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.1 | exim4-base 4.99.1-1ubuntu1.1 | Apr 29, 2026 |
| exim4-config · Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | exim4-config 4.93-13ubuntu1.12+esm1 | Jun 24, 2026 |
| exim4-config · Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.7 | exim4-config 4.95-4ubuntu2.7 | May 15, 2026 |
| exim4-config · Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.4 | exim4-config 4.97-4ubuntu4.4 | May 15, 2026 |
| exim4-config · Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.1 | exim4-config 4.98.2-1ubuntu2.1 | May 15, 2026 |
| exim4-config · Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.1 | exim4-config 4.99.1-1ubuntu1.1 | Apr 29, 2026 |
| exim4-daemon-heavy · Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | exim4-daemon-heavy 4.93-13ubuntu1.12+esm1 | Jun 24, 2026 |
| exim4-daemon-heavy · Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.7 | exim4-daemon-heavy 4.95-4ubuntu2.7 | May 15, 2026 |
| exim4-daemon-heavy · Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.4 | exim4-daemon-heavy 4.97-4ubuntu4.4 | May 15, 2026 |
| exim4-daemon-heavy · Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.1 | exim4-daemon-heavy 4.98.2-1ubuntu2.1 | May 15, 2026 |
| exim4-daemon-heavy · Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.1 | exim4-daemon-heavy 4.99.1-1ubuntu1.1 | Apr 29, 2026 |
| exim4-daemon-light · Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | exim4-daemon-light 4.93-13ubuntu1.12+esm1 | Jun 24, 2026 |
| exim4-daemon-light · Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.7 | exim4-daemon-light 4.95-4ubuntu2.7 | May 15, 2026 |
| exim4-daemon-light · Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.4 | exim4-daemon-light 4.97-4ubuntu4.4 | May 15, 2026 |
| exim4-daemon-light · Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.1 | exim4-daemon-light 4.98.2-1ubuntu2.1 | May 15, 2026 |
| exim4-daemon-light · Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.1 | exim4-daemon-light 4.99.1-1ubuntu1.1 | Apr 29, 2026 |
| eximon4 · Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | eximon4 4.93-13ubuntu1.12+esm1 | Jun 24, 2026 |
| eximon4 · Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.7 | eximon4 4.95-4ubuntu2.7 | May 15, 2026 |
| eximon4 · Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.4 | eximon4 4.97-4ubuntu4.4 | May 15, 2026 |
| eximon4 · Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.1 | eximon4 4.98.2-1ubuntu2.1 | May 15, 2026 |
| eximon4 · Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.1 | eximon4 4.99.1-1ubuntu1.1 | Apr 29, 2026 |
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