{"answers":{"affected":"6 open source packages ship an affected version, including github.com/gofiber/fiber/v2 and github.com/gofiber/fiber/v3. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42554 exists.","fix":"Upgrade github.com/gofiber/fiber/v2 to 2.52.13 or later.","what":"CVE-2026-42554 is a medium-severity cross-site scripting vulnerability in gofiber fiber, published on 11 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-42554 and fix it if it is affected.\n\nWhat it is: CVE-2026-42554 is a medium-severity cross-site scripting vulnerability in gofiber fiber, published on 11 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42554 exists.\n\nAffected packages and fixed versions:\n- github.com/gofiber/fiber/v2 (Go): affected all versions; fixed in 2.52.13\n- github.com/gofiber/fiber/v2 (Go): affected all versions; fixed in 2.52.13\n- github.com/gofiber/fiber/v2 (Go): affected all versions; fixed in 2.52.13\n- github.com/gofiber/fiber/v3 (Go): affected all versions; fixed in 3.2.0\n- github.com/gofiber/fiber/v3 (Go): affected all versions; fixed in 3.2.0\n- github.com/gofiber/fiber/v3 (Go): affected all versions; fixed in 3.2.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-42554/ (Markdown: https://insights.sbomify.com/CVE-2026-42554/index.md)","id":"CVE-2026-42554","markdown":"https://insights.sbomify.com/CVE-2026-42554/index.md","name":"CVE-2026-42554","record":{"aliases":["GHSA-qjv7-627w-8qjv","GO-2026-5585"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution"],"network_reachable":"yes","non_default_config":true,"product_category":"Go web framework","requires_auth":"none","summary":"Remote attackers can inject arbitrary HTML/JavaScript via the Accept header when developers use the AutoFormat feature in the Go Fiber web framework.","user_interaction":"required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"fiber","vendor":"gofiber"}],"cvss":{"score":5.3,"severity":"medium","source":"cna","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","version":"4.0"},"cwes":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation"}],"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.","ecosystems":["Go"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"Fiber: XSS in AutoFormat Content Negotiation","id":"CVE-2026-42554","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":null,"products":[],"type":"xss","year":"2026"},"n_packages":6,"n_references":1,"next":{"headline":"Valtimo: SpEL injection via StandardEvaluationContext allows Remote Code Execution by admin users","id":"CVE-2026-42555"},"packages":[{"ecosystem":"Go","fixed":["2.52.13"],"introduced":["0"],"last_affected":[],"package":"github.com/gofiber/fiber/v2","purl":null,"source":"GHSA-qjv7-627w-8qjv"},{"ecosystem":"Go","fixed":["2.52.13"],"introduced":["0"],"last_affected":[],"package":"github.com/gofiber/fiber/v2","purl":"pkg:golang/github.com/gofiber/fiber/v2","source":"GHSA-qjv7-627w-8qjv"},{"ecosystem":"Go","fixed":["2.52.13"],"introduced":["0"],"last_affected":[],"package":"github.com/gofiber/fiber/v2","purl":"pkg:golang/github.com/gofiber/fiber/v2","source":"GO-2026-5585"},{"ecosystem":"Go","fixed":["3.2.0"],"introduced":["0"],"last_affected":[],"package":"github.com/gofiber/fiber/v3","purl":null,"source":"GHSA-qjv7-627w-8qjv"},{"ecosystem":"Go","fixed":["3.2.0"],"introduced":["0"],"last_affected":[],"package":"github.com/gofiber/fiber/v3","purl":"pkg:golang/github.com/gofiber/fiber/v3","source":"GHSA-qjv7-627w-8qjv"},{"ecosystem":"Go","fixed":["3.2.0"],"introduced":["0"],"last_affected":[],"package":"github.com/gofiber/fiber/v3","purl":"pkg:golang/github.com/gofiber/fiber/v3","source":"GO-2026-5585"}],"prev":{"headline":"Cinny: Access token disclosure via invalidated emoji pack avatar URL in service worker","id":"CVE-2026-42553"},"products":["fiber"],"published":"2026-05-11","related":[{"cvss_score":10,"headline":"Fiber Session Middleware Token Injection Vulnerability","id":"CVE-2024-38513","kev_date_added":null,"published":"2024-07-01"},{"cvss_score":10,"headline":"CSRF Token Reuse Vulnerability in fiber","id":"CVE-2023-45128","kev_date_added":null,"published":"2023-10-16"},{"cvss_score":9.4,"headline":"Fiber has Insecure CORS Configuration, Allowing Wildcard Origin with Credentials","id":"CVE-2024-25124","kev_date_added":null,"published":"2024-02-21"},{"cvss_score":9.2,"headline":"Fiber insecurely fallsback in utils.UUIDv4() / utils.UUID() — predictable / zero‑UUID on crypto/rand failure","id":"CVE-2025-66630","kev_date_added":null,"published":"2026-02-09"},{"cvss_score":8.7,"headline":"Fiber Susceptible to Crash via `BodyParser` Due to Unvalidated Large Slice Index in Decoder","id":"CVE-2025-54801","kev_date_added":null,"published":"2025-08-05"},{"cvss_score":8.6,"headline":"CSRF Token Validation Vulnerability in fiber","id":"CVE-2023-45141","kev_date_added":null,"published":"2023-10-16"},{"cvss_score":7.7,"headline":"Fiber has an Arbitrary File Read in Static Middleware on Windows","id":"CVE-2026-25891","kev_date_added":null,"published":"2026-02-24"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"Go Vulnerability Database","prefix":"GO"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-05-15","vendors":["gofiber"]},"summary":"Remote attackers can inject arbitrary HTML/JavaScript via the Accept header when developers use the AutoFormat feature in the Go Fiber web framework.","url":"https://insights.sbomify.com/CVE-2026-42554/"}