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Matrix Irc BridgeApplication · Matrix

CVE-2022-39203

HIGH · 8.8 CVSS v3.1 Published 2022-09-13
Fix available
A fix is available. Upgrade to 0.35.0 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
matrix-appservice-irc is an open source Node.js IRC bridge for Matrix. Attackers can specify a specific string of characters, which would confuse the bridge into combining an attacker-owned channel and an existing channel, allowing them to grant themselves permissions in the channel. The vulnerability has been patched in matrix-appservice-irc 0.35.0. As a workaround operators may disable dynamic channel joining via `dynamicChannels.enabled` to prevent users from joining new channels, which prevents any new channels being bridged outside of what is already bridged, and what is specified in the config.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

matrix-appservice-irc fails to properly sanitize channel names, allowing attackers to specify a specific string that tricks the bridge into merging an attacker-controlled channel with an existing legitimate channel. This channel confusion enables privilege escalation by granting the attacker permissions in the target channel.

MitigationUpgrade to matrix-appservice-irc version 0.35.0 or higher. Alternatively, disable dynamic channel creation by setting `dynamicChannels.enabled: false` in the bridge configuration to prevent users from joining new channels.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Matrix Irc BridgeApplication
Affected:< 0.35.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check the installed version of matrix-appservice-irc
    Run `npm list matrix-appservice-irc` or check the package.json file in the bridge installation directory for the version field
    Affected if The version listed is less than 0.35.0 (e.g., 0.34.0, 0.33.0, etc.)
  2. Locate the bridge configuration file
    Find the config.yaml or equivalent configuration file used by the matrix-appservice-irc deployment, typically in the config directory of the bridge installation
    Affected if The configuration file exists and is readable
  3. Verify if dynamic channel creation is enabled
    Inspect the configuration file for the `dynamicChannels.enabled` setting. If this setting is absent, dynamic channels are enabled by default
    Affected if `dynamicChannels.enabled` is set to true OR is not explicitly set to false (the default behavior enables dynamic channels)

The environment is affected if the installed matrix-appservice-irc version is below 0.35.0 AND dynamic channel creation (dynamicChannels.enabled) is not explicitly set to false in the configuration.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.35.0 or later
Fixed in 0.35.0
Interim mitigation

Upgrade to matrix-appservice-irc version 0.35.0 or higher. Alternatively, disable dynamic channel creation by setting `dynamicChannels.enabled: false` in the bridge configuration to prevent users from joining new channels.

Recommended fix High confidence

0.35.0

  1. Check current installed version of matrix-appservice-irc (e.g., npm list matrix-appservice-irc or check package.json)
  2. Backup your current configuration and data directory
  3. Upgrade to version 0.35.0 using your package manager (e.g., npm install [email protected] or yarn upgrade [email protected])
  4. Restart the bridge service to load the new version
  5. Verify the upgrade was successful by checking the version number
  6. Test IRC-Matrix bridging functionality to ensure normal operation
  7. If upgrade is not immediately possible, apply the workaround: set `dynamicChannels.enabled: false` in the bridge configuration to prevent dynamic channel joining

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Matrix Irc Bridge Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing3.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,210
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,936.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-39203 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data