Vulnerability · Published Sep 24, 2026 · Assigned by GitHub_M

CVE-2026-85738TREK: SSRF Guard Bypass via IPv6 Transition Addresses (NAT64/6to4)

Medium 6.3

In plain English

A medium-severity server-side request forgery in TREK from liketrek. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities).

Severity (CVSS 3.1)6.3Medium

Exploit odds (30 days)0.4%top 67.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
liketrek	TREK	< 3.4.0

Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

References

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