Description
A pointer overflow, with code execution, was discovered in ZeroMQ libzmq (aka 0MQ) 4.2.x and 4.3.x before 4.3.1. A v2_decoder.cpp zmq::v2_decoder_t::size_ready integer overflow allows an authenticated attacker to overwrite an arbitrary amount of bytes beyond the bounds of a buffer, which can be leveraged to run arbitrary code on the target system. The memory layout allows the attacker to inject OS commands into a data structure located immediately after the problematic buffer (i.e., it is not necessary to use a typical buffer-overflow exploitation technique that changes the flow of control).
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 | 4.3.1-1 | — |
| Debian 13 | zeromq3 | 4.3.1-1 | — |
| Debian 12 | zeromq3 | 4.3.1-1 | — |
| Debian 9 | zeromq3 | 4.2.1-4+deb9u1 | DSA-4368-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | zeromq3 | 4.2.5-1ubuntu0.1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 | zeromq | 4.2.3-3.3.2 | SUSE-SU-2019:0110-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-pyzmq | 27.1.0-3.1 | openSUSE-SU-2026:11459-1 |
| openSUSE Tumbleweed | zeromq | 4.3.4-2.2 | openSUSE-SU-2024:11540-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | zeromq | 4.3.1-r0 | — |
| Alpine v3.23 | zeromq | 4.3.1-r0 | — |
| Alpine v3.22 | zeromq | 4.3.1-r0 | — |
| Alpine v3.21 | zeromq | 4.3.1-r0 | — |
| Alpine v3.20 | zeromq | 4.3.1-r0 | — |
Show 14 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | zeromq | 4.3.1-r0 | — |
| Alpine v3.18 | zeromq | 4.3.1-r0 | — |
| Alpine v3.17 | zeromq | 4.3.1-r0 | — |
| Alpine v3.16 | zeromq | 4.3.1-r0 | — |
| Alpine v3.15 | zeromq | 4.3.1-r0 | — |
| Alpine v3.14 | zeromq | 4.3.1-r0 | — |
| Alpine v3.13 | zeromq | 4.3.1-r0 | — |
| Alpine v3.12 | zeromq | 4.3.1-r0 | — |
| Alpine v3.11 | zeromq | 4.3.1-r0 | — |
| Alpine v3.10 | zeromq | 4.3.1-r0 | — |
| Alpine v3.9 | zeromq | 4.3.1-r0 | — |
| Alpine v3.8 | zeromq | 4.2.5-r0 | — |
| Alpine v3.7 | zeromq | 4.2.5-r0 | — |
| Alpine v3.6 | zeromq | 4.2.5-r0 | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
GitHub 2 repositories
-
AkashicYiTai/CVE-2019-6250-libzmq ★ 1 · Jun 20, 2024
-
dinosn/cve-2019-6250-lab ★ 0 · May 3, 2026
End-to-end pre-auth RCE lab for CVE-2019-6250 (libzmq <= 4.3.0, ZMTP/2.0 wire-protocol)
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 4
- openSUSE-SU-2026:11459-1 python313-pyzmq-27.1.0-3.1 on GA media SUSE / openSUSE Security Updates · Aug 6, 2026
- DSA-4368-1 zeromq3 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:11540-1 libzmq5-32bit-4.3.4-2.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:0110-1 Security update for zeromq SUSE / openSUSE Security Updates · May 2, 2025
References
- DSA-4368 vendor-advisory
- https://github.com/zeromq/libzmq/issues/3351
- https://github.com/zeromq/libzmq/releases/tag/v4.3.1
- GLSA-201903-22 vendor-advisory