CVE-2026-119285
Fiber: CORS wildcard origins matched without a dot boundary, allowing credentialed cross-origin reads
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.
Fixes and workarounds
Fix
github.com/gofiber/fiber/v2 (Go): OSV reports a fixed version 2.52.3. Check the advisory for supported release branches.
Source: OSV GHSA-g5jq-qmqr-qrwfAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| fiber gofiber |
>= 2.52.1, < 2.52.3 (affected) | CNA: GitHub_M |
github.com/gofiber/fiber/v2github.com/gofiber/fiber/v2
Go |
≥ 2.52.1; < 2.52.3 (affected, semver); OSV events: introduced 2.52.1; fixed 2.52.3Source events (semver)Other versions: unaffected |
OSV GHSA-g5jq-qmqr-qrwf |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 5.9 medium |
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N | CNA: GitHub_M |
Exploit evidence
- https://github.com/gofiber/fiber/security/advisories/GHSA-g5jq-qmqr-qrwf
exploit · ADP: CISA-ADP
References
- https://github.com/gofiber/fiber/security/advisories/GHSA-g5jq-qmqr-qrwfCNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/gofiber/fiber/pull/2915CNA: GitHub_M · x_refsource_MISC
- https://github.com/gofiber/fiber/commit/1aac6f618b6bd3e159d2449acb4232a2170b976bCNA: GitHub_M · x_refsource_MISC
- https://github.com/gofiber/fiber/releases/tag/v2.52.3CNA: GitHub_M · x_refsource_MISC
- https://github.com/gofiber/fiber/security/advisories/GHSA-g5jq-qmqr-qrwfADP: CISA-ADP · exploit
- https://github.com/advisories/GHSA-g5jq-qmqr-qrwfOSV / GitHub Security Advisories · advisory
- https://osv.dev/vulnerability/GHSA-g5jq-qmqr-qrwfOSV / GitHub Security Advisories · osv
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