GHSA-wm4w-7h2q-3pf7
MEDIUMMatrix IRC Bridge truncated content of messages can be leaked
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
matrix-appservice-ircnpmDescription
Impact
The matrix-appservice-irc before version 2.0.0 can be exploited to leak the truncated body of a message if a malicious user sends a Matrix reply to an event ID they don't have access to. As a precondition to the attack, the malicious user needs to know the event ID of the message they want to leak, as well as to be joined to both the Matrix room and the IRC channel it is bridged to.
The message reply containing the leaked message content is visible to IRC channel members when this happens.
Patches
matrix-appservice-irc 2.0.0 checks whether the user has permission to view an event before constructing a reply. Administrators should upgrade to this version.
Workarounds
It's possible to limit the amount of information leaked by setting a reply template that doesn't contain the original message. See these lines in the configuration file.
References
https://github.com/matrix-org/matrix-appservice-irc/pull/1799
For more information
If you have any questions or comments about this advisory, please email us at security at matrix.org.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | matrix-appservice-irc | all versions | 2.0.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for matrix-appservice-irc. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update matrix-appservice-irc to 2.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wm4w-7h2q-3pf7 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-wm4w-7h2q-3pf7 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-wm4w-7h2q-3pf7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-wm4w-7h2q-3pf7 in your dependencies?
O3 detects GHSA-wm4w-7h2q-3pf7 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.