Fiber is an Express inspired web framework written in Go. From 2.52.1 until 2.52.3, the CORS middleware's validateDomain wildcard matcher in middleware/cors/utils.go strips the scheme and checks only a host suffix without requiring a dot boundary. An application configured with a wildcard-subdomain AllowOrigins value and AllowCredentials enabled can reflect an unrelated attacker-controlled origin whose host merely ends with the configured base domain. A user who visits that origin can expose authenticated cross-origin responses to the attacker's page; empty-label origins and later comma-space parsing hardening are outside this advisory. This issue is fixed in version 2.52.3.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 1
- First seenCVSS 5.9 · gofiberNVD modified 2026-10-29 21:36
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 4
- https://github.com/gofiber/fiber/security/advisories/GHSA-g5jq-qmqr-qrwf x_refsource_confirm
- https://github.com/gofiber/fiber/pull/2915 x_refsource_misc
- https://github.com/gofiber/fiber/commit/1aac6f618b6bd3e159d2449acb4232a2170b976b x_refsource_misc
- https://github.com/gofiber/fiber/releases/tag/v2.52.3 x_refsource_misc