Description
The STARTTLS feature in Exim through 4.94.2 allows response injection (buffering) during MTA SMTP sending.
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 | 4.95~RC2-1 | — |
| Debian 13 | exim4 | 4.95~RC2-1 | — |
| Debian 12 | exim4 | 4.95~RC2-1 | — |
| Debian 11 | exim4 | 4.94.2-7+deb11u4 | DLA-3938-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | exim4 | 4.93-13ubuntu1.11 | USN-6881-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | exim4 | 4.90.1-1ubuntu1.10+esm4 | USN-6881-1 |
| Ubuntu Pro 16.04 LTS | exim4 | 4.86.2-2ubuntu2.6+esm7 | USN-6881-1 |
| Ubuntu Pro 14.04 LTS | exim4 | 4.82-3ubuntu2.4+esm8 | USN-6881-1 |
Advisories 3
- USN-6881-1 exim4 vulnerability Ubuntu Security Notices (USN) · Jun 29, 2026
- DLA-3938-1 exim4 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- WID-SEC-2023-0877 Exim: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Oct 28, 2024