Critical severity · published May 28, 2021
CVE-2021-20236
A flaw was found in the ZeroMQ server in versions before 4.3.3
9.8
CVSS
1.9%
EPSS
No
On KEV
Description
A flaw was found in the ZeroMQ server in versions before 4.3.3. This flaw allows a malicious client to cause a stack buffer overflow on the server by sending crafted topic subscription requests and then unsubscribing. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.9% · higher than 79% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CS
Ceph Storage · Redhat
2.0 · source: NVD
EL
Enterprise Linux · Redhat
7.0 · source: NVD
FE
Fedora · Fedoraproject
33 · source: NVD
ZE
Zeromq · Zeromq
before 4.3.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-20236
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-20236
Issue Tracking
https://bugzilla.redhat.com/show_bug.cgi?id=1921976
Patch
https://github.com/zeromq/libzmq/security/advisories/GHSA-qq65-x72m-9wr8
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