High severity · published May 28, 2021
CVE-2021-20237
An uncontrolled resource consumption (memory leak) flaw was found in ZeroMQ's src/xpub.cpp in versions before 4.3.3
7.5
CVSS
1.7%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.7% · higher than 77% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Libzmq · Zeromq
4.2.0 before 4.3.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-20237
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-20237
Issue Tracking
https://bugzilla.redhat.com/show_bug.cgi?id=1921989
Patch
https://github.com/zeromq/libzmq/security/advisories/GHSA-4p5v-h92w-6wxw
More from Libzmq
9.8
CVE-2020-36400
ZeroMQ libzmq 4.3.3 has a heap-based buffer overflow in zmq::tcp_read, a different vulnerability than CVE-2021-20235
9.8
CVE-2019-13132
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 to a libzmq application, running with a socket listening…
8.8
CVE-2019-6250
A pointer overflow, with code execution, was discovered in ZeroMQ libzmq (aka 0MQ) 4.2.x and 4.3.x before 4.3.1
8.1
CVE-2021-20235
There's a flaw in the zeromq server in versions before 4.3.3 in src/decoder_allocators.hpp
7.5
CVE-2020-15166
In ZeroMQ before version 4.3.3, there is a denial-of-service vulnerability