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Fencer Vulns
medium 6.5

CVE-2026-53859 json

OpenClaw < 2026.5.26 - Hostname Validation Bypass via Trailing-Dot Inconsistency

published 2026-06-16 4 mo ago modified 2026-06-18 4 mo ago also GHSA-gxg4-2rrr-jhc7 , EUVD-2026-37161

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

OpenClaw before 2026.5.26 contains a hostname validation vulnerability allowing attackers to bypass blocklist comparisons using trailing-dot notation in model or workspace-derived URLs. Attackers can exploit inconsistent hostname checks to reach destinations that operators intended to block through hostname policies.

Patch / fix

  • npm openclaw 2026.5.26
  • OpenClaw OpenClaw 2026.5.26

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 6.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CNA 4.0 6.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
GitHub 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
npm openclaw
<2026.5.26
2026.5.26

Affected products

  • OpenClaw OpenClaw

Classification

Weakness
  • CWE-1023 Incomplete Comparison with Missing Factors
  • CWE-918 Server-Side Request Forgery
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.