CVE & CISA-KEV Catalog

CVE-2021-20235

HIGHEPSS 99th pctl
8.1
CVSS v3
NVD

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.

How to fix

Remediation Available
zeromq3Debian
Fixed in:4.3.3-1CVE-2021-20235
Fixed in:4.3.3-1CVE-2021-20235
Fixed in:4.3.3-1CVE-2021-20235
Fixed in:4.3.3-1CVE-2021-20235
libzmq3Ubuntu
Fixed in:4.0.4+dfsg-2ubuntu0.1+esm3USN-4920-1
libzmq5Ubuntu
Fixed in:4.1.4-7ubuntu0.1+esm2USN-4920-1
Fixed in:4.2.5-1ubuntu0.2+esm2USN-4920-1
Fixed in:4.3.2-2ubuntu1.20.04.1~esm2USN-4920-1
zeromq3Ubuntu
Fixed in:4.0.4+dfsg-2ubuntu0.1+esm3USN-4920-1
Fixed in:4.1.4-7ubuntu0.1+esm2USN-4920-1
Fixed in:4.2.5-1ubuntu0.2+esm2USN-4920-1
Fixed in:4.3.2-2ubuntu1.20.04.1~esm2USN-4920-1

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Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

43.86%probability of exploitation in 30 days
99thpercentile

Very high risk: more likely to be exploited than 99% of all known CVEs.

References

Related Vulnerabilities

Other CWE-120 (Classic Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2014-0195Medium6.8100%-Fix
CVE-2017-7269Critical9.8100%KEV-
CVE-2019-11043High8.799%KEV + RansomFix
CVE-2011-4862High10.095%-Fix
CVE-2007-5659High7.894%KEVFix
CVE-2022-3786High7.592%-Fix
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CVE-2021-20235 severity badge

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.