SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

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.

MEDIUM 6.3EPSS 0.19%

Does this matter?

Lower severity and a low EPSS score (0.19%). Track it; it rarely justifies an emergency change on its own.

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 4.0
6.3 MEDIUMCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.19% probability · 9th percentile
CISA KEV
Not listed
Weakness
CWE-636
Affected
openclaw/openclaw
Source
disclosure@vulncheck.com

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.