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TI-2026-82781 Aliases CVE-2026-119285GHSA-g5jq-qmqr-qrwf

Fiber CORS wildcard origin match ignores dot boundary

Priority MEDIUM 60CWE-346Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
High
Impact type
Security bypass
Confidentiality · integrity · availability
High · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-346.

Summary

Fiber from 2.52.1 before 2.52.3 has a flaw in the CORS middleware's wildcard origin matching, which checks only a host suffix without requiring a dot boundary (CWE-346). An application that sets a wildcard subdomain AllowOrigins value and enables AllowCredentials reflects an unrelated origin whose host merely ends with the base domain. When a user visits that attacker-controlled origin, the attacker's page can read authenticated cross-origin responses.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00129 2nd percentileScored 2026-11-07
Fix Fixed fiber (gofiber): 2.52.3github.com/gofiber/fiber/v2 (Go): 2.52.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
gofiberfiber2.52.1 to before 2.52.32.52.3Patch availableCNA
—github.com/gofiber/fiber/v2 (Go)2.52.1 to before 2.52.32.52.3Patch availableGHSA-g5jq-qmqr-qrwf
  • fiber Vendorgofiber Affected 2.52.1 to before 2.52.3 Fixed in 2.52.3 Patch available CNA
  • github.com/gofiber/fiber/v2 (Go) Vendor— Affected 2.52.1 to before 2.52.3 Fixed in 2.52.3 Patch available GHSA-g5jq-qmqr-qrwf

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:gofiber:fiber:*:*:*:*:*:*:*:*——gofiber
  • cpe:2.3:a:gofiber:fiber:*:*:*:*:*:*:*:* Versions — — ·gofiber

Remediation

Upgrade the gofiber/fiber product and the github.com/gofiber/fiber/v2 Go module to version 2.52.3, which fixes the issue.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA fiber (gofiber) Fixed in 2.52.3
  • Fix · GHSA-g5jq-qmqr-qrwf github.com/gofiber/fiber/v2 (Go) Fixed in 2.52.3 Advisory →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-29 Threatist record created from CVE-2026-119285
  2. 2026-10-30 Alias added: GHSA-g5jq-qmqr-qrwf
  3. 2026-10-30 Fix available: Go/github.com/gofiber/fiber/[email protected] · GHSA-g5jq-qmqr-qrwf
  4. 2026-10-30 CVSS score added · GHSA-g5jq-qmqr-qrwf
  5. 2026-10-30 Weakness changed · GHSA-g5jq-qmqr-qrwf
  6. 2026-10-30 6 new references · GHSA-g5jq-qmqr-qrwf
  7. 2026-10-31 Priority changed: MEDIUM → LOW
  8. 2026-11-04 CISA SSVC decision points changed
  9. 2026-11-04 Priority changed: LOW → MEDIUM
  10. 2026-11-06 Affected versions changed · Red Hat
  11. 2026-11-06 CVSS score added · Red Hat

References

Advisory 1

Other 5

  • TI-2025-40976 Fiber Utils UUIDv4 and UUID Silent Fallback to Predictable Values CVSS 4.0CRITICAL 9.3
  • TI-2025-34555 Fiber Susceptible to Crash via `BodyParser` Due to Unvalidated Large Slice Index in Decoder CVSS 4.0HIGH 8.7
  • TI-2024-16578 Fiber has Insecure CORS Configuration, Allowing Wildcard Origin with Credentials CVSS 3.1CRITICAL 9.8
  • TI-2025-30446 Fiber panics when fiber.Ctx.BodyParser parses invalid range index CVSS 4.0HIGH 7.7
  • TI-2026-23477 github.com/gofiber/fiber/v3 cache middleware can mix responses across query parameters CVSS 3.1MEDIUM 6.5
  • TI-2026-20922 Fiber has a Denial of Service Vulnerability via Route Parameter Overflow CVSS 4.0MEDIUM 5.5
See all 19 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences