Vulnerability Description
Fiber is a web framework for Go. Prior to 2.52.12 and 3.1.0, Cross-Site Scripting vulnerability in Go Fiber allows a remote attacker to inject arbitrary HTML/JavaScript by supplying Accept: text/html on any request whose handler passes attacker-influenced data to the AutoFormat() feature. The developer opts into content negotiation by calling AutoFormat(), but does not opt into raw HTML emission for a particular request; Fiber chooses that branch from attacker-controlled Accept. The html branch is the sole outlier in a method whose name (AutoFormat) and symmetrical structure actively telegraph "safe, format-agnostic reply." This vulnerability is fixed in 2.52.12 and 3.1.0.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Gofiber | Fiber | < 2.52.12 |
Related Weaknesses (CWE)
References
- https://github.com/gofiber/fiber/security/advisories/GHSA-qjv7-627w-8qjvExploitMitigationVendor Advisory
- https://github.com/gofiber/fiber/security/advisories/GHSA-qjv7-627w-8qjvExploitMitigationVendor Advisory
FAQ
What is CVE-2026-42554?
CVE-2026-42554 is a vulnerability with a CVSS score of 6.1 (MEDIUM). Fiber is a web framework for Go. Prior to 2.52.12 and 3.1.0, Cross-Site Scripting vulnerability in Go Fiber allows a remote attacker to inject arbitrary HTML/JavaScript by supplying Accept: text/html ...
How severe is CVE-2026-42554?
CVE-2026-42554 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-42554?
Check the references section above for vendor advisories and patch information. Affected products include: Gofiber Fiber.