OpenClaw: Mattermost handlers could fall open when channel type was missing (CVE-2026-53837) | HOL Guard CVE

Medium · CVSS 3.7CVE-2026-53837GHSA-GP79-M99V-GJMH

OpenClaw: Mattermost handlers could fall open when channel type was missing

Answer in brief

CVE-2026-53837 records a Medium severity (CVSS 3.7) vulnerability in OpenClaw: Mattermost handlers could fall open when channel type was missing. The current sources do not mark it as known exploited. The current feed maps openclaw (npm). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jul 2, 2026Updated Aug 28, 2026Source checked Aug 28, 2026First seen by HOL Jul 2, 2026Material review Aug 28, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 3.7
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 3.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps openclaw (npm). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
openclawnpm	<=2026.5.5	2026.5.6

Recommended response

Check inventory. Check lockfiles and deployed manifests for openclaw.
Review the reported fix. Update openclaw to 2026.5.6 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jul 2, 2026
Evidence: source:ghsa:source_dates:source-dates:record
Source modified
Aug 28, 2026
Evidence: source:ghsa:source_dates:source-dates:record
First seen by HOL
Jul 2, 2026

Sources and claim methodology

Upstream source description

### Summary Mattermost handlers could fall open when channel type was missing. In affected versions, a Mattermost event missing channel type metadata could continue without applying the intended DM policy decision. This advisory is scoped to the named feature and configuration. It does not change OpenClaw's trusted-operator model: authenticated Gateway operators, installed plugins, and intentional local execution surfaces remain trusted unless a separate policy, approval, allowlist, sandbox, or auth boundary is crossed. ### Impact When the affected feature is enabled and reachable, this could process a Mattermost event that should have been gated by channel policy. Practical impact depends on the operator's configuration and whether lower-trust input can reach that path. ### Patched Versions The first stable patched version is `2026.5.6`. ### Mitigations keep Mattermost bot access restricted and review channel metadata errors until patched. As general hardening, keep channel and tool allowlists narrow, avoid sharing one Gateway between mutually untrusted users, and disable the affected feature when it is not needed.

Quoted source text, attributed separately from HOL analysis.