{"id":"CVE-2026-45045","sourceIdentifier":"security-advisories@github.com","published":"2026-07-08T20:16:50.060","lastModified":"2026-07-15T20:50:55.160","vulnStatus":"Analyzed","cveTags":[],"descriptions":[{"lang":"en","value":"Fiber is an Express inspired web framework written in Go. Prior to 3.3.0 and 2.52.14, the BalancerForward proxy helper in middleware/proxy/proxy.go uses Header.Add() instead of Header.Set() when injecting X-Real-IP, allowing an attacker-supplied first X-Real-IP value to be forwarded to upstream servers for logging, rate limiting, and access control. This issue is fixed in version 3.3.0 and 2.52.14."}],"affected":[{"source":"security-advisories@github.com","affectedData":[{"vendor":"gofiber","product":"fiber","versions":[{"version":">= 3.0.0-beta.2, < 3.3.0","status":"affected"},{"version":"< 2.52.14","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":1.4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-07-09T13:19:42.395861Z","id":"CVE-2026-45045","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-290"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:gofiber:fiber:*:*:*:*:*:go:*:*","versionEndExcluding":"2.52.14","matchCriteriaId":"34B804BA-609E-4B3E-80E0-D1D3EC25E3F0"},{"vulnerable":true,"criteria":"cpe:2.3:a:gofiber:fiber:*:*:*:*:*:go:*:*","versionStartIncluding":"3.0.0","versionEndExcluding":"3.3.0","matchCriteriaId":"A091E1AB-E012-47CA-9674-734334483EF0"}]}]}],"references":[{"url":"https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d","source":"security-advisories@github.com","tags":["Patch"]},{"url":"https://github.com/gofiber/fiber/pull/4260","source":"security-advisories@github.com","tags":["Issue Tracking","Patch"]},{"url":"https://github.com/gofiber/fiber/pull/4495","source":"security-advisories@github.com","tags":["Issue Tracking","Patch"]},{"url":"https://github.com/gofiber/fiber/releases/tag/v2.52.14","source":"security-advisories@github.com","tags":["Release Notes"]},{"url":"https://github.com/gofiber/fiber/releases/tag/v3.3.0","source":"security-advisories@github.com","tags":["Release Notes"]},{"url":"https://github.com/gofiber/fiber/security/advisories/GHSA-gcfq-8gqf-4876","source":"security-advisories@github.com","tags":["Exploit","Vendor Advisory"]}]}