CVE-2026-85738

MEDIUM 6.3

TREK: SSRF Guard Bypass via IPv6 Transition Addresses (NAT64/6to4)

CVSS Score

6.3

EPSS Score

0.0%

EPSS Percentile

0th

TREK is a collaborative travel planner. Prior to 3.4.0, the checkSsrf logic in server/src/utils/ssrfGuard.ts does not recognize NAT64, 6to4, or Teredo IPv6 transition addresses that encode an IPv4 destination. An authenticated user who controls a DNS record can supply a URL whose AAAA result is a transition address embedding a private, loopback, or link-local IPv4 target, and isAlwaysBlocked and isPrivateNetwork classify the address as allowed. In a deployment that routes the applicable transition format, user-facing imports, webhooks, integrations, or plugin egress can reach internal services or cloud metadata and expose returned information. This issue is fixed in version 3.4.0.

CWE	CWE-918
Vendor	liketrek
Product	trek
Published	Sep 24, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Attack Vector

Network

Attack Complexity

High

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

None

Availability

None

Affected Versions

liketrek / TREK

< 3.4.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/liketrek/TREK/security/advisories/GHSA-9hpq-mrpx-mcxg github.com: https://github.com/liketrek/TREK/pull/1540 github.com: https://github.com/liketrek/TREK/commit/a2bd9be184a94997105ce190dad920c41e7b10df github.com: https://github.com/liketrek/TREK/releases/tag/v3.4.0