Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Exim | Exim | < 4.99.2 | 4.99.2 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | exim4 | 4.99.2-1 | — |
| Debian 13 | exim4 | 4.98.2-1+deb13u2 | — |
| Debian 12 | exim4 | 4.96-15+deb12u9 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | exim4 | 4.99.1-1ubuntu1.1 | — |
| Ubuntu 25.10 | exim4 | 4.98.2-1ubuntu2.1 | — |
| Ubuntu 24.04 LTS | exim4 | 4.97-4ubuntu4.4 | — |
| Ubuntu 22.04 LTS | exim4 | 4.95-4ubuntu2.7 | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | exim4 | 4.93-13ubuntu1.12+esm1 | USN-8382-1 |
| Ubuntu Pro 18.04 LTS | exim4 | 4.90.1-1ubuntu1.10+esm6 | USN-8382-1 |
| Ubuntu Pro 16.04 LTS | exim4 | 4.86.2-2ubuntu2.6+esm9 | USN-8382-1 |
| Ubuntu Pro 14.04 LTS | exim4 | 4.82-3ubuntu2.4+esm9 | USN-8382-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | exim | 4.98.2-r0 | — |
| Alpine v3.23 | exim | 4.98.2-r0 | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | exim +9 | 4.99.5-r0 | — |
Advisories 2
- WID-SEC-2026-1334 Exim und cPanel/WHM: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 13, 2026
- USN-8382-1 exim4 vulnerabilities Ubuntu Security Notices (USN) · Jun 4, 2026