CVE-2026-40686
Fixed in a distro release EPSS <1%CVSS 3.7
In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.
Products: exim
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Chainguard | exim | 4.99.5-r0 |
| Chainguard | exim-cdb | 4.99.5-r0 |
| Chainguard | exim-dbmdb | 4.99.5-r0 |
| Chainguard | exim-dnsdb | 4.99.5-r0 |
| Chainguard | exim-doc | 4.99.5-r0 |
| Chainguard | exim-mysql | 4.99.5-r0 |
| Chainguard | exim-pgsql | 4.99.5-r0 |
| Chainguard | exim-scripts | 4.99.5-r0 |
| Chainguard | exim-sqlite | 4.99.5-r0 |
| Chainguard | exim-utils | 4.99.5-r0 |
| Debian:12 | exim4 | 4.96-15+deb12u9 |
| Debian:13 | exim4 | 4.98.2-1+deb13u2 |
| Debian:14 | exim4 | 4.99.2-1 |
| Ubuntu:22.04:LTS | exim4 | 4.95-4ubuntu2.7 |
| Ubuntu:24.04:LTS | exim4 | 4.97-4ubuntu4.4 |
| Ubuntu:25.10 | exim4 | 4.98.2-1ubuntu2.1 |
| Ubuntu:26.04:LTS | exim4 | 4.99.1-1ubuntu1.1 |
| Ubuntu:Pro:14.04:LTS | exim4 | no fix |
| Ubuntu:Pro:14.04:LTS | exim4 | 4.82-3ubuntu2.4+esm9 |
| Ubuntu:Pro:16.04:LTS | exim4 | no fix |
| Ubuntu:Pro:16.04:LTS | exim4 | 4.86.2-2ubuntu2.6+esm9 |
| Ubuntu:Pro:18.04:LTS | exim4 | no fix |
| Ubuntu:Pro:18.04:LTS | exim4 | 4.90.1-1ubuntu1.10+esm6 |
| Ubuntu:Pro:20.04:LTS | exim4 | 4.93-13ubuntu1.12+esm1 |
| Wolfi | exim | 4.99.5-r0 |
| Wolfi | exim-cdb | 4.99.5-r0 |
| Wolfi | exim-dbmdb | 4.99.5-r0 |
| Wolfi | exim-dnsdb | 4.99.5-r0 |
| Wolfi | exim-doc | 4.99.5-r0 |
| Wolfi | exim-mysql | 4.99.5-r0 |
| Wolfi | exim-pgsql | 4.99.5-r0 |
| Wolfi | exim-scripts | 4.99.5-r0 |
| Wolfi | exim-sqlite | 4.99.5-r0 |
| Wolfi | exim-utils | 4.99.5-r0 |