CVE-2026-53837

Description

OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted content.

CVSS v3.1 Score

3.7

LOW

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

EPSS — Exploit Prediction

0.0019

Probability of exploitation

0.09%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-636 CWE-636

Affected Products

Vendor	Product	Versions
openclaw	openclaw	< 2026.5.6

References

Advisories & Patches

https://github.com/openclaw/openclaw/security/advisories/GHSA-gp79-m99v-gjmh

Other References

https://www.vulncheck.com/advisories/openclaw-missing-channel-type-validation-in-mattermost-event-handlers

Frequently Asked Questions

What is CVE-2026-53837? +

OpenClaw before 2026.5.6 contains an improper access control vulnerability in Mattermost event handlers that fails to validate channel type metadata. Attackers can bypass intended DM policy decisions by sending crafted Mattermost events missing channel type information to process restricted content. It has a CVSS v3.1 base score of 3.7 (LOW).

How severe is CVE-2026-53837? +

CVE-2026-53837 has a CVSS v3.1 score of 3.7 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0019, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-53837? +

CVE-2026-53837 affects products from openclaw, specifically: openclaw. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-53837? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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