CVE-2026-119285

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CVE-2026-119285

Summary: Fiber: CORS wildcard origins matched without a dot boundary, allowing credentialed cross-origin reads

Details: 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.

References: https://github.com/gofiber/fiber/releases/tag/v2.52.3, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/119xxx/CVE-2026-119285.json, https://github.com/gofiber/fiber/security/advisories/GHSA-g5jq-qmqr-qrwf, https://nvd.nist.gov/vuln/detail/CVE-2026-119285, https://github.com/gofiber/fiber/commit/1aac6f618b6bd3e159d2449acb4232a2170b976b, https://github.com/gofiber/fiber/pull/2915