CVE-2023-38700
matrix-appservice-irc events can be crafted to leak parts of targeted messages from other bridged rooms
matrix-appservice-irc is a Node.js IRC bridge for Matrix. Prior to version 1.0.1, it was possible to craft an event such that it would leak part of a targeted message event from another bridged room. This required knowing an event ID to target. Version 1.0.1n fixes this issue. As a workaround, set the matrixHandler.eventCacheSize config value to 0. This workaround may impact performance.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
matrix-appservice-irc events can be crafted to leak parts of targeted messages from other bridged rooms
matrix-appservice-irc is a Node.js IRC bridge for Matrix. Prior to version 1.0.1, it was possible to craft an event such that it would leak part of a targeted message event from another bridged room. This required knowing an event ID to target. Version 1.0.1n fixes this issue. As a workaround, set the matrixHandler.eventCacheSize config value to 0. This workaround may impact performance.
- Record
CVE-2023-38700- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N - Weakness
- CWE-200
- Updated
- 2026-11-02
EUVDEUVD-2023-2268
matrix-appservice-irc is a Node.js IRC bridge for Matrix. Prior to version 1.0.1, it was possible to craft an event such that it would leak part of a targeted message event from another bridged room. This required knowing an event ID to target. Version 1.0.1n fixes this issue. As a workaround, set the matrixHandler.eventCacheSize config value to 0. This workaround may impact performance.
- Record
EUVD-2023-2268- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-c7hh-3v6c-fj4q
matrix-appservice-irc events can be crafted to leak parts of targeted messages from other bridged rooms
Impact
It was possible to craft an event such that it would leak part of a targeted message event from another bridged room. This required knowing an event ID to target.
Patches
Please upgrade to 1.0.1.
Workarounds
You can set the matrixHandler.eventCacheSize config value to 0 to workaround this bug. However, this may impact performance.
Credits
Discovered and reported by Val Lorentz.
For more information
If you have any questions or comments about this advisory email us at [email protected].
- Record
GHSA-c7hh-3v6c-fj4q- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N - Weakness
- CWE-200
- Updated
- 2026-11-02
NVD
matrix-appservice-irc is a Node.js IRC bridge for Matrix. Prior to version 1.0.1, it was possible to craft an event such that it would leak part of a targeted message event from another bridged room. This required knowing an event ID to target. Version 1.0.1n fixes this issue. As a workaround, set the matrixHandler.eventCacheSize config value to 0. This workaround may impact performance.
- Record
CVE-2023-38700- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N - CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-200
- Updated
- 2026-11-02
OSV
matrix-appservice-irc events can be crafted to leak parts of targeted messages from other bridged rooms
matrix-appservice-irc is a Node.js IRC bridge for Matrix. Prior to version 1.0.1, it was possible to craft an event such that it would leak part of a targeted message event from another bridged room. This required knowing an event ID to target. Version 1.0.1n fixes this issue. As a workaround, set the matrixHandler.eventCacheSize config value to 0. This workaround may impact performance.
- Record
CVE-2023-38700- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N - Weakness
- CWE-200
- Updated
- 2026-11-02
OSVGHSA-c7hh-3v6c-fj4q
matrix-appservice-irc events can be crafted to leak parts of targeted messages from other bridged rooms
Impact
It was possible to craft an event such that it would leak part of a targeted message event from another bridged room. This required knowing an event ID to target.
Patches
Please upgrade to 1.0.1.
Workarounds
You can set the matrixHandler.eventCacheSize config value to 0 to workaround this bug. However, this may impact performance.
Credits
Discovered and reported by Val Lorentz.
For more information
If you have any questions or comments about this advisory email us at [email protected].
- Record
GHSA-c7hh-3v6c-fj4q- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N - Weakness
- CWE-200
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
matrix-appservice-ircnpm |
through 1.0.0 | 1.0.1 |
matrix-appservice-ircnpm |
before 1.0.1 | 1.0.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-38700 is a low vulnerability (CVSS 3.5) in Matrix Irc Bridge, published August 4, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.60%, the 48th percentile. Fixed in matrix-appservice-irc 1.0.1.
References
github.com/matrix-org/matrix-appservice-irc/security/advisories/GHSA-c7hh-3v6c-fj4q
nvd.nist.gov/vuln/detail/CVE-2023-38700