CVE-2023-38690: matrix-appservice-irc IRC command injection via admin commands containing newlines

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-08-04 · updated 2026-06-17
Weakness: CWE-20

Description

matrix-appservice-irc is a Node.js IRC bridge for Matrix. Prior to version 1.0.1, it is possible to craft a command with newlines which would not be properly parsed. This would mean you could pass a string of commands as a channel name, which would then be run by the IRC bridge bot. Versions 1.0.1 and above are patched. There are no robust workarounds to the bug. One may disable dynamic channels in the config to disable the most common execution method but others may exist.

Affected products

matrix-org matrix-appservice-irc: before 1.0.1 — fixed in 1.0.1

How to fix

Upgrade to a fixed version: matrix-org matrix-appservice-irc 1.0.1. Check the vendor advisory for mitigations.

References

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