Vulnerability · Published May 28, 2021 · Assigned by redhat

CVE-2021-20237

High 7.5

In plain English

A high-severity uncontrolled resource consumption in zeromq. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.7% (higher than 77% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)7.5High

Exploit odds (30 days)1.7%top 22.8% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official description

An uncontrolled resource consumption (memory leak) flaw was found in ZeroMQ's src/xpub.cpp in versions before 4.3.3. This flaw allows a remote unauthenticated attacker to send crafted PUB messages that consume excessive memory if the CURVE/ZAP authentication is disabled on the server, causing a denial of service. The highest threat from this vulnerability is to system availability.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	zeromq3	4.3.3-1	DEBIAN-CVE-2021-20237
Debian:13	zeromq3	4.3.3-1	DEBIAN-CVE-2021-20237
Debian:14	zeromq3	4.3.3-1	DEBIAN-CVE-2021-20237

Affected products (as reported)

Vendor	Product	Versions
n/a	zeromq	zeromq 4.3.3

Weakness: CWE-400

References

https://bugzilla.redhat.com/show_bug.cgi?id=1921989 x_refsource_MISC
https://github.com/zeromq/libzmq/security/advisories/GHSA-4p5v-h92w-6wxw x_refsource_MISC