CVE-2026-53839: OpenClaw < 2026.5.7 - Hostname Prefix Matching Bypass in Trusted Retry Endpoint Validation

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-12 · updated 2026-10-08
Weakness: CWE-1023

Description

OpenClaw before 2026.5.7 contains a hostname validation vulnerability in retry endpoint checks that allows matching hostname prefixes instead of exact hostnames. Attackers can exploit this by crafting a hostname prefix resembling a trusted host to send authentication material to untrusted endpoints.

Affected products

OpenClaw: before 2026.5.7 — fixed in 2026.5.7

How to fix

Upgrade to a fixed version: OpenClaw 2026.5.7. Check the vendor advisory for mitigations.

References

https://github.com/openclaw/openclaw/security/advisories/GHSA-77q5-rr5v-x43q
https://www.vulncheck.com/advisories/openclaw-hostname-prefix-matching-bypass-in-trusted-retry-endpoint-validation

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