Out-of-bounds Write Affecting zeromq3 package, versions <4.3.3-1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
3.09% (87th percentile)

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  • Snyk IDSNYK-DEBIAN14-ZEROMQ3-11775412
  • published10 Aug 2025
  • disclosed1 Apr 2021

Introduced: 1 Apr 2021

CVE-2021-20235  (opens in a new tab)
CWE-787  (opens in a new tab)
CWE-120  (opens in a new tab)

How to fix?

Upgrade Debian:14 zeromq3 to version 4.3.3-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream zeromq3 package and not the zeromq3 package as distributed by Debian. See How to fix? for Debian:14 relevant fixed versions and status.

There's a flaw in the zeromq server in versions before 4.3.3 in src/decoder_allocators.hpp. The decoder static allocator could have its sized changed, but the buffer would remain the same as it is a static buffer. A remote, unauthenticated attacker who sends a crafted request to the zeromq server could trigger a buffer overflow WRITE of arbitrary data if CURVE/ZAP authentication is not enabled. The greatest impact of this flaw is to application availability, data integrity, and confidentiality.

CVSS Base Scores

version 3.1