Libzmq
CVE-2021-20235
HIGH
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
1DescriptionNVD
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.
AnalysisAI
There's a flaw in the zeromq server in versions before 4.3.3 in src/decoder_allocators.hpp. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. This Buffer Copy without Size Check vulnerability could allow attackers to overflow a buffer to corrupt adjacent memory.
Technical ContextAI
This vulnerability is classified as Buffer Copy without Size Check (CWE-120), which allows attackers to overflow a buffer to corrupt adjacent memory. 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 products include: Zeromq Libzmq. Version information: before 4.3.3.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Always validate buffer sizes before copy operations. Use bounded functions (strncpy, snprintf). Enable compiler protections.
A pointer overflow, with code execution, was discovered in ZeroMQ libzmq (aka 0MQ) 4.2.x and 4.3.x before 4.3.1. Rated h
An uncontrolled resource consumption (memory leak) flaw was found in the ZeroMQ client in versions before 4.3.3 in src/p
In ZeroMQ libzmq before 4.0.9, 4.1.x before 4.1.7, and 4.2.x before 4.3.2, a remote, unauthenticated client connecting t
An uncontrolled resource consumption (memory leak) flaw was found in ZeroMQ's src/xpub.cpp in versions before 4.3.3. Rat
In ZeroMQ before version 4.3.3, there is a denial-of-service vulnerability. Rated high severity (CVSS 7.5), this vulnera
Same weakness CWE-120 – Classic Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
Leaving vuln.today