CVE-2022-39203

Name: CVE-2022-39203
Creator: NVD / NIST
Published: 2022-09-13T19:15:13.03+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 0.72%

Last modified Jun 17, 2026

CVE-2022-39203 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. matrix-appservice-irc is an open source Node.js IRC bridge for Matrix. Attackers can specify a specific string of characters, which would confuse the bridge into combining an attacker-owned channel and an existing channel, allowing them to grant themselves permissions in the channel. EPSS estimates a 0.72% chance of exploitation in the next 30 days.

Description

matrix-appservice-irc is an open source Node.js IRC bridge for Matrix. Attackers can specify a specific string of characters, which would confuse the bridge into combining an attacker-owned channel and an existing channel, allowing them to grant themselves permissions in the channel. The vulnerability has been patched in matrix-appservice-irc 0.35.0. As a workaround operators may disable dynamic channel joining via `dynamicChannels.enabled` to prevent users from joining new channels, which prevents any new channels being bridged outside of what is already bridged, and what is specified in the config.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.72%

49.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-269

Affected Software

Vendor	Product	Versions
Matrix	Matrix Irc Bridge	< 0.35.0

References

https://github.com/matrix-org/matrix-appservice-irc/security/advisories/GHSA-xvqg-mv25-rwvwMitigation, Third Party Advisory
https://matrix.org/blog/2022/09/13/security-release-of-matrix-appservice-irc-0-35-0-high-severity/Vendor Advisory
https://github.com/matrix-org/matrix-appservice-irc/security/advisories/GHSA-xvqg-mv25-rwvwMitigation, Third Party Advisory
https://matrix.org/blog/2022/09/13/security-release-of-matrix-appservice-irc-0-35-0-high-severity/Vendor Advisory

Timeline

Published: Sep 13, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-39203?

How severe is CVE-2022-39203?

CVE-2022-39203 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.72% probability of exploitation in the next 30 days.

How do I fix CVE-2022-39203?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2022-39203?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST