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Vulnerability · Published Apr 1, 2021 · Assigned by redhat

CVE-2021-20235

High 8.1

In plain English

A high-severity buffer overflow in zeromq. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 43.9% (higher than 99% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)8.1High
Exploit odds (30 days)43.9%top 1.2% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12zeromq34.3.3-1DEBIAN-CVE-2021-20235
Debian:13zeromq34.3.3-1DEBIAN-CVE-2021-20235
Debian:14zeromq34.3.3-1DEBIAN-CVE-2021-20235

Affected products (as reported)

VendorProductVersions
n/a zeromq zeromq 4.3.3

Weakness: CWE-120

References