Description
libzmq before 4.0.6 and 4.1.x before 4.1.1 allows remote attackers to conduct downgrade attacks and bypass ZMTP v3 protocol security mechanisms via a ZMTP v2 or earlier header.
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 | zeromq3 | 4.0.5+dfsg-3 | — |
| Debian 13 | zeromq3 | 4.0.5+dfsg-3 | — |
| Debian 12 | zeromq3 | 4.0.5+dfsg-3 | — |
| Debian 8 | zeromq3 | 4.0.5+dfsg-2+deb8u1 | DSA-3255-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | zeromq3 | 4.0.4+dfsg-2ubuntu0.1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 | zeromq | 4.0.4-13.1 | SUSE-SU-2015:1510-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Enterprise Storage 1.0 | zeromq | 4.0.4-13.1 | SUSE-SU-2015:1510-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | zeromq | 4.2.0-1.1 | openSUSE-SU-2024:10038-1 |
Advisories 3
- DSA-3255-1 zeromq3 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2015:1510-1 Security update for zeromq SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10038-1 libzmq5-4.2.0-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://github.com/zeromq/zeromq4-x/commit/b6e3e0f601e2c1ec1f3aac880ed6a3fe63043e51
- DSA-3255 vendor-advisory
- FEDORA-2015-8635 vendor-advisory
- openSUSE-SU-2015:1028 vendor-advisory
- https://github.com/zeromq/libzmq/issues/1273