{"cve":"CVE-2026-25899","nvd":{"published":"2026-02-24T22:16:31.613","modified":"2026-06-17T10:25:24.327","status":"Analyzed","description":"Fiber is an Express inspired web framework written in Go. In versions on the v3 branch prior to 3.1.0, the use of the `fiber_flash` cookie can force an unbounded allocation on any server. A crafted 10-character cookie value triggers an attempt to allocate up to 85GB of memory via unvalidated msgpack deserialization. No authentication is required. Every GoFiber v3 endpoint is affected regardless of whether the application uses flash messages. Version 3.1.0 fixes the issue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-770","CWE-789"],"references":["https://github.com/gofiber/fiber/releases/tag/v3.1.0","https://github.com/gofiber/fiber/security/advisories/GHSA-2mr3-m5q5-wgp6"],"products":["gofiber:fiber"],"source":"nvd","synced_at":"2026-10-19T22:24:17.937441719+00:00"},"epss":{"cve":"CVE-2026-25899","score":0.0045,"percentile":0.39137,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-2mr3-m5q5-wgp6","url":"https://osv.dev/vulnerability/GHSA-2mr3-m5q5-wgp6","summary":"Fiber is Vulnerable to Denial of Service via Flash Cookie Unbounded Allocation","modified":"2026-02-27T20:37:07Z","packages":[{"ecosystem":"Go","name":"github.com/gofiber/fiber/v3","purl":"pkg:golang/github.com/gofiber/fiber/v3","ranges":["<3.1.0"],"fixed":["3.1.0"]}]},{"id":"GO-2026-4534","url":"https://osv.dev/vulnerability/GO-2026-4534","summary":"Fiber is Vulnerable to Denial of Service via Flash Cookie Unbounded Allocation in github.com/gofiber/fiber/v3","modified":"2026-02-26T18:56:15.314415Z","packages":[{"ecosystem":"Go","name":"github.com/gofiber/fiber/v3","purl":"pkg:golang/github.com/gofiber/fiber/v3","ranges":["<3.1.0"],"fixed":["3.1.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}