{"id":"CVE-2026-42554","revision":"45f5e9be095b4d0d8768d79810ed32d7","records":[{"revision":"45f5e9be095b4d0d8768d79810ed32d7","observedAt":"2026-10-27T11:12:04.713+00:00","statement":{"source":"nvd","id":"CVE-2026-42554","aliases":[],"title":"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 atta…","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":"2026-05-11T23:19:48.083+00:00","modifiedAt":"2026-10-26T18:10:00.173+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · security-advisories@github.com · Secondary","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","score":5.3,"severity":"MEDIUM"},{"system":"CVSS 3.1 · nvd@nist.gov · Primary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1,"severity":"MEDIUM"}],"references":["https://github.com/gofiber/fiber/security/advisories/GHSA-qjv7-627w-8qjv"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-42554","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Analyzed","weaknesses":["CWE-79"],"productCriteria":["cpe:2.3:a:gofiber:fiber:*:*:*:*:*:go:*:*"],"sourceDates":{"published":"2026-05-11T23:19:48.083","lastModified":"2026-10-26T18:10:00.173"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-42554","identifiers":["CVE-2026-42554"]},"retained":false,"historicalAffected":[]}],"coverage":[]}