matrix-appservice-irc IRC command injection via admin commands containing newlines

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.0 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N

EPSS

• CVE-2023-38690: 0.86% estimated exploitation activity in the next 30 days; percentile 58.66 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact 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. Patches Versions 1.0.1 and above are patched. Workarounds There are no robust workarounds to the bug. You can disable dynamic channels in the config to disable the most common execution method but others may exist. It is highly recommended to upgrade the bridge. Credits Discovered and reported by Val Lorentz. For more information If you have any questions or comments about this advisory email us at security@matrix.org.

Published by the source

4 Aug 2023, 17:26 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 12:30 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-3pmj-jqqp-2mj3

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-3pmj-jqqp-2mj3

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# Patch Next advisory brief: CVE-2023-38690

Advisory: matrix-appservice-irc IRC command injection via admin commands containing newlines
IDs: CVE-2023-38690, GHSA-3pmj-jqqp-2mj3
Record: https://patchnext.com/advisories/cve-2023-38690 (revision 2, source checked 26 Oct 2026, 12:30 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: matrix-appservice-irc 1.0.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm matrix-appservice-irc: affected <= 1.0.0; fixed in 1.0.1

## Suggested inspection (read-only)
- `npm ls matrix-appservice-irc --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on matrix-appservice-irc.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-3pmj-jqqp-2mj3 (OSV record GHSA-3pmj-jqqp-2mj3 lists affected ranges: npm matrix-appservice-irc >=0 <1.0.1 (fixed))
- Verified: https://github.com/advisories/GHSA-3pmj-jqqp-2mj3 (GitHub-reviewed advisory GHSA-3pmj-jqqp-2mj3 lists affected ranges: npm matrix-appservice-irc >=0 <=1.0.0)

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