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CVE-2026-53859 OpenClaw CVE debrief

CVE-2026-53859 is a MEDIUM-severity vulnerability in OpenClaw, a software that contains a hostname validation vulnerability. This vulnerability allows attackers to bypass blocklist comparisons using trailing-dot notation in model or workspace-derived URLs. As a result, attackers can reach destinations that operators intended to block through hostname policies.

Vendor
OpenClaw
Product
Unknown
CVSS
MEDIUM 6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-16
Original CVE updated
2026-06-17
Advisory published
2026-06-16
Advisory updated
2026-06-17

Who should care

Users of OpenClaw before version 2026.5.26 should apply patches to prevent exploitation.

Technical summary

The vulnerability exists due to inconsistent hostname checks in OpenClaw. Specifically, the software does not properly handle trailing dots in URLs, allowing attackers to bypass blocklist comparisons. This can lead to unintended access to blocked destinations.

Defensive priority

MEDIUM

Recommended defensive actions

  • Apply patches to update OpenClaw to version 2026.5.26 or later.
  • Review and update hostname policies to account for trailing-dot notation.

Evidence notes

Evidence of this vulnerability can be found in the CVE record [cve-org] and the NVD detail page [nvd]. Additional information is available in the source references [ref-4] and [ref-5].

Sources and references

Verified primary and authoritative sources

  • CVE-2026-53859 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-53859

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-53859 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-53859

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.