Description
In fetchmail before 6.5.6, the SMTP client can crash when authenticating upon receiving a 334 status code in a malformed context.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| fetchmail | fetchmail | 5.9.9 – < 6.5.6 | 6.5.6 |
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 | fetchmail | 6.5.6-1 | — |
| Debian 13 | fetchmail | No fix yet | — |
| Debian 12 | fetchmail | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | fetchmail | 6.6.6-1ubuntu0.1 | USN-9013-1 |
| Ubuntu 26.04 LTS | fetchmail | 6.5.4-0ubuntu2 | USN-9013-1 |
| Ubuntu 25.10 | fetchmail | 6.5.4-0ubuntu2 | — |
| Ubuntu 24.04 LTS | fetchmail | 6.4.38-1ubuntu4.1 | USN-9013-1, USN-7838-1 |
| Ubuntu 22.04 LTS | fetchmail | 6.4.27-1ubuntu0.1 | USN-9013-1, USN-7838-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | fetchmail | 6.4.2-2ubuntu0.1~esm1 | USN-9013-1 |
| Ubuntu Pro 18.04 LTS | fetchmail | 6.3.26-3ubuntu0.1~18.04.1+esm1 | USN-9013-1 |
| Ubuntu Pro 16.04 LTS | fetchmail | 6.3.26-2ubuntu0.1~esm1 | USN-9013-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | fetchmail | 6.4.22-150600.35.3.1 | SUSE-SU-2025:3845-1 |
| SLES 15 SP6 | fetchmail | 6.4.22-150600.35.3.1 | SUSE-SU-2025:3845-1 |
| SLES 12 SP5 | fetchmail | 6.3.26-13.21.1 | SUSE-SU-2025:3966-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | fetchmail | 6.5.2-160000.3.1 | SUSE-SU-2026:20935-1 |
| SLES 16.0 | fetchmail | 6.5.2-160000.3.1 | SUSE-SU-2026:20935-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | fetchmail | 6.5.6-1.1 | openSUSE-SU-2025:15653-1 |
| openSUSE Leap 16.0 | fetchmail | 6.5.2-160000.3.1 | openSUSE-SU-2026:20432-1 |
| openSUSE Leap 15.6 | fetchmail | 6.4.22-150600.35.3.1 | SUSE-SU-2025:3845-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | fetchmail | 6.5.6-r0 | — |
| Alpine v3.23 | fetchmail | 6.5.6-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | fetchmail | 6.5.7-1.amzn2023 | ALAS2023-2025-1292 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | fetchmail | No fix yet | — |
| Azure Linux 2 (CBL-Mariner) | fetchmail | No fix yet | — |
Advisories 10
- USN-9013-1 fetchmail vulnerabilities Ubuntu Security Notices (USN) · Nov 11, 2026
- WID-SEC-2026-1730 Xerox FreeFlow Print Server: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff BSI CERT-Bund (WID) · Jul 16, 2026
- USN-7838-1 fetchmail vulnerability Ubuntu Security Notices (USN) · Apr 27, 2026
- openSUSE-SU-2026:20432-1 Security update for fetchmail SUSE / openSUSE Security Updates · Apr 3, 2026
- SUSE-SU-2026:20935-1 Security update for fetchmail SUSE / openSUSE Security Updates · Apr 2, 2026
- WID-SEC-2025-2202 fetchmail: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Apr 1, 2026
- openSUSE-SU-2025:15653-1 fetchmail-6.5.6-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:3966-1 Security update for fetchmail SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:3845-1 Security update for fetchmail SUSE / openSUSE Security Updates · Mar 23, 2026
- ALAS2023-2025-1292 Moderate: fetchmail security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Dec 8, 2025