CVE-2014-7203: libzmq (aka ZeroMQ/C++) 4.0.x before 4.0.5 does not ensure that nonces are unique, which allows man-in-the-mid

Routine

MEDIUM 4.3DOWNGRADE

CVE-2014-7203 is a medium-severity flaw (CVSS 4.3) affecting zeromq. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

libzmq (aka ZeroMQ/C++) 4.0.x before 4.0.5 does not ensure that nonces are unique, which allows man-in-the-middle attackers to conduct replay attacks via unspecified vectors.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	4.3 (Medium)
EPSS exploit chance	1.9% (top 20%)
CISA exploited list	No
Published	2014-10-08
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: zeromq

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2014-10-08 19:55 UTCPublished CVE record published
2026-06-17 00:14 UTCUpdated Record last modified

zeromq zeromq DOWNGRADE

Affected: 4.0.0 · 4.0.1 · 4.0.2 · 4.0.3 · 4.0.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.0.0

1. Check installed version

apt-cache policy zeromq || rpm -q zeromq || zeromq --version

2. No fixed release: DOWNGRADE to a release before 4.0.0 (Debian / Ubuntu)

apt-cache madison zeromq sudo apt install zeromq=<VERSION_BEFORE_4.0.0> sudo apt-mark hold zeromq

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list zeromq sudo dnf downgrade zeromq-<VERSION_BEFORE_4.0.0> sudo dnf versionlock add zeromq

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2014-7203?

zeromq: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2014-7203 being exploited?

CVE-2014-7203 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2014-7203 affect?

CVE-2014-7203 affects zeromq. Severity is medium (CVSS 4.3). libzmq (aka ZeroMQ/C++) 4.0.x before 4.0.5 does not ensure that nonces are unique, which allows man-in-the-middle attackers to conduct replay attacks via unspecified vectors.

How urgent is CVE-2014-7203?

Priority 35/100. No elevated risk signals yet.

Related CVEs

CVE-2021-20236 CRITICAL 9.8 UPGRADE DOWNGRADE A flaw was found in the ZeroMQ server in versions before 4.3.3
CVE-2014-9721 MEDIUM 4.3 UPGRADE libzmq before 4.0.6 and 4.1.x before 4.1.1 allows remote attackers to conduct downgrade attacks and bypass ZMT
CVE-2014-7202 MEDIUM 4.3 DOWNGRADE stream_engine.cpp in libzmq (aka ZeroMQ/C++)) 4.0.5 before 4.0.5 allows man-in-the-middle attackers to conduct

References

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