# CVE-2024-39691: Matrix AppService IRC message content leak via timestamp spoofing

Source: https://junglewise.ai/threats/cve-2024-39691-matrix-appservice-irc-message-content-leak-via-timestamp-spoofing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2024-07-05. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2024-39691 · Severity: low · CVSS 3.1 · Published 2024-07-05

The Matrix AppService IRC bridge is software that relays messages between Matrix chat rooms and IRC channels. A malicious Matrix server can trick the bridge into leaking message content from rooms it shouldn't access by fabricating timestamps, potentially exposing private chat messages to unauthorized parties.

Technologies: [Matrix.org Appservice IRC](https://junglewise.ai/threats/technologies/appservice-irc), [matrix-appservice-irc (npm)](https://junglewise.ai/threats/technologies/matrix-appservice-irc). Vendors: [Matrix.org](https://junglewise.ai/threats/vendors/matrix-org), [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2024-39691 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2024-39691 being exploited in the wild.

**How severe is CVE-2024-39691?** Low severity, with a CVSS score of 3.1, published 5 July 2024.

**Which products and versions are affected?** Matrix.org Appservice IRC <= 2.0.0; matrix-appservice-irc (npm) SEMVER:introduced=0,fixed=2.0.1.

**Is there a fix for CVE-2024-39691?** Yes. matrix-appservice-irc (npm): upgrade to 2.0.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2024-39691 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2024-39691?** Check whether you run Matrix.org Appservice IRC or matrix-appservice-irc (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- matrix-appservice-irc (npm): upgrade to 2.0.1 or later

  ```sh
  npm install matrix-appservice-irc@2.0.1
  ```


## Technical details

The vulnerability is an insecure data validation issue (CWE-280, CWE-755) in the matrix-appservice-irc bridge. The bridge uses a homeserver-provided timestamp (origin_server_ts) to determine if a user has access to an event before including truncated message content in IRC replies. Since an external Matrix homeserver controls this timestamp, a malicious homeserver can fabricate it to bypass access control checks and trick the bridge into leaking room messages it should not have visibility into. The attack requires the malicious homeserver to be joined to a room with the bridge. Fixed in version 2.0.1 by replacing timestamp-based validation with internally-tracked event timestamps.

## Affected products

- Matrix.org AppService IRC <= 2.0.0

## Identifiers

- CVE-2024-39691
- GHSA-w9mh-5x8j-9754

## Timeline

- 2024-07-05: disclosed
- 2024-07-05: patched: Version 2.0.1 released

## References

- [https://github.com/matrix-org/matrix-appservice-irc/security/advisories/GHSA-w9mh-5x8j-9754](https://github.com/matrix-org/matrix-appservice-irc/security/advisories/GHSA-w9mh-5x8j-9754)

## Related threats

- [Matrix IRC Bridge command injection in puppeted user](https://junglewise.ai/threats/cve-2025-27146-matrix-irc-bridge-command-injection-in-puppeted-user)
- [Matrix IRC Bridge message content information disclosure](https://junglewise.ai/threats/cve-2024-32000-matrix-irc-bridge-message-content-information-disclosure)
- [Matrix matrix-appservice-irc IRC command injection via newlines](https://junglewise.ai/threats/cve-2023-38690-matrix-matrix-appservice-irc-irc-command-injection-via-newlines)
- [Matrix AppService IRC information disclosure in event handling](https://junglewise.ai/threats/cve-2023-38700-matrix-appservice-irc-information-disclosure-in-event-handling)
- [Matrix-appservice-irc SQL injection via roomIds argument](https://junglewise.ai/threats/cve-2022-3971-matrix-appservice-irc-sql-injection-via-roomids-argument)