CVE-2026-27818Network attack vector

Unauthenticated SSRF via suffix-only hostname validation

Published Feb 26, 2026 · Updated Feb 26, 2026

SSRF in the proxy controller in TerriaJS-Server before 4.0.3 allows remote attackers to relay requests to disallowed domains. The allowlist test accepts any hostname ending with an allowed domain, so attacker-controlled maliciousexample.com matches example.com without a dot boundary. Network access to the proxy endpoint and a configured allowed domain are required; successful exploitation turns the server into an unauthorized relay to the attacker-controlled host.

CVSS severity8.7
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in the proxy controller in TerriaJS-Server before 4.0.3 allows remote attackers to relay requests to disallowed domains. The allowlist test accepts any hostname ending with an allowed domain, so attacker-controlled maliciousexample.com matches example.com without a dot boundary. Network access to the proxy endpoint and a configured allowed domain are required; successful exploitation turns the server into an unauthorized relay to the attacker-controlled host.

The record

CVE
CVE-2026-27818
Published
Feb 26, 2026
Updated
Feb 26, 2026
Vendor
Terria
Product
TerriaJS-Server
Classifications
CWE-20, CWE-918, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.0.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Terria · TerriaJS-Serverversion=< 4.0.3

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
8.7GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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