{"id":"CVE-2026-42554","revision":"84a0fbde1cac4b2eb1b5e8bfc445365a","records":[{"revision":"84a0fbde1cac4b2eb1b5e8bfc445365a","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-42554","aliases":[],"title":"Fiber: XSS in AutoFormat Content Negotiation","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.","state":0,"publishedAt":"2026-05-11T21:47:17.133+00:00","modifiedAt":"2026-05-15T18:24:38.3+00:00","affected":[{"ecosystem":"Vendor product","name":"fiber","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"gofiber\",\n                    \"product\": \"fiber\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 2.52.13\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \">= 3.0.0-beta.2, < 3.1.0\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","score":5.3,"severity":"MEDIUM"}],"references":["https://github.com/gofiber/fiber/security/advisories/GHSA-qjv7-627w-8qjv"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-42554","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-42554","identifiers":["CVE-2026-42554"]},"retained":false,"historicalAffected":[]}],"coverage":[]}