CVE-2021-20235: Buffer Overflow
A flaw was found in zeromq before 4.3.3. The use of a static allocator with ZMTP v1 packets may lead to a heap based overflow.
References:
https://github.com/zeromq/libzmq/pull/3902 https://github.com/zeromq/libzmq/security/advisories/GHSA-fc3w-qxf5-7hp6 https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=21984
Other sources
There's a flaw in the zeromq server in versions before 4.3.3 in src/decoderallocators.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.
— Launchpad
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the vulnerability ID for this flaw in the zeromq server?
The vulnerability ID is CVE-2021-20235.
What is the severity of CVE-2021-20235?
The severity of CVE-2021-20235 is high, with a severity value of 8.1.
What is the affected software for CVE-2021-20235?
The affected software for CVE-2021-20235 includes versions before 4.3.3 of zeromq server.
How can an attacker exploit CVE-2021-20235?
A remote, unauthenticated attacker can exploit CVE-2021-20235 by sending a crafted request to the zeromq server.
Where can I find more information about CVE-2021-20235?
You can find more information about CVE-2021-20235 on the CVE Mitre website.