8.1
HIGH CVSS 3.1
CVE-2021-20235
ZeroMQ Buffer Overflow Vulnerability
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.

INFO

Published Date :

April 1, 2021, 2:15 p.m.

Last Modified :

Nov. 21, 2024, 5:46 a.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2021-20235 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Zeromq libzmq
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 MEDIUM [email protected]
CVSS 3.1 HIGH [email protected]
Solution
The zeromq server is vulnerable to a buffer overflow; updating the affected packages will remediate the vulnerability.
  • Update the libzmq packages.
  • Consult the vendor advisory for specific upgrade instructions.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-20235.

URL Resource
https://bugzilla.redhat.com/show_bug.cgi?id=1921983 Issue Tracking Patch Third Party Advisory
https://github.com/zeromq/libzmq/security/advisories/GHSA-fc3w-qxf5-7hp6 Patch Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1921983 Issue Tracking Patch Third Party Advisory
https://github.com/zeromq/libzmq/security/advisories/GHSA-fc3w-qxf5-7hp6 Patch Third Party Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-20235 is associated with the following CWEs:

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-20235 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-20235 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=1921983
    Added Reference https://github.com/zeromq/libzmq/security/advisories/GHSA-fc3w-qxf5-7hp6
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Nov. 07, 2023

    Action Type Old Value New Value
    Removed CWE Red Hat, Inc. CWE-787
  • Reanalysis by [email protected]

    Aug. 05, 2022

    Action Type Old Value New Value
    Added CWE NIST CWE-787
  • Initial Analysis by [email protected]

    Apr. 06, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:M/Au:N/C:P/I:P/A:P)
    Added CVSS V3.1 NIST AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
    Changed Reference Type https://bugzilla.redhat.com/show_bug.cgi?id=1921983 No Types Assigned https://bugzilla.redhat.com/show_bug.cgi?id=1921983 Issue Tracking, Patch, Third Party Advisory
    Changed Reference Type https://github.com/zeromq/libzmq/security/advisories/GHSA-fc3w-qxf5-7hp6 No Types Assigned https://github.com/zeromq/libzmq/security/advisories/GHSA-fc3w-qxf5-7hp6 Patch, Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:a:zeromq:libzmq:*:*:*:*:*:*:*:* versions from (including) 4.2.0 up to (excluding) 4.3.3
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 8.1
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 6.8
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

3.09 }} 0.20%

score

0.86249

percentile