{"id":"CVE-2026-45045","state":"PUBLISHED","title":"Fiber: X-Real-IP Spoofing via Header.Add() in BalancerForward","description":"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.","publishedAt":"2026-07-08T19:26:26.580Z","updatedAt":"2026-07-09T13:20:08.367Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["gofiber fiber"],"affected":[{"vendor":"gofiber","product":"fiber","versions":[{"version":">= 3.0.0-beta.2, < 3.3.0","status":"affected"},{"version":"< 2.52.14","status":"affected"}]}],"references":["https://github.com/gofiber/fiber/security/advisories/GHSA-gcfq-8gqf-4876","https://github.com/gofiber/fiber/pull/4260","https://github.com/gofiber/fiber/pull/4495","https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396","https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d","https://github.com/gofiber/fiber/releases/tag/v2.52.14","https://github.com/gofiber/fiber/releases/tag/v3.3.0"],"weaknesses":["CWE-290"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/45xxx/CVE-2026-45045.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-45045","state":"PUBLISHED","datePublished":"2026-07-08T19:26:26.580Z","dateUpdated":"2026-07-09T13:20:08.367Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-08T18:07:27.341Z"},"containers":{"cna":{"title":"Fiber: X-Real-IP Spoofing via Header.Add() in BalancerForward","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":[{"vendor":"gofiber","product":"fiber","versions":[{"version":">= 3.0.0-beta.2, < 3.3.0","status":"affected"},{"version":"< 2.52.14","status":"affected"}]}],"references":[{"url":"https://github.com/gofiber/fiber/security/advisories/GHSA-gcfq-8gqf-4876","name":"https://github.com/gofiber/fiber/security/advisories/GHSA-gcfq-8gqf-4876","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/gofiber/fiber/pull/4260","name":"https://github.com/gofiber/fiber/pull/4260","tags":["x_refsource_MISC"]},{"url":"https://github.com/gofiber/fiber/pull/4495","name":"https://github.com/gofiber/fiber/pull/4495","tags":["x_refsource_MISC"]},{"url":"https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396","name":"https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396","tags":["x_refsource_MISC"]},{"url":"https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d","name":"https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d","tags":["x_refsource_MISC"]},{"url":"https://github.com/gofiber/fiber/releases/tag/v2.52.14","name":"https://github.com/gofiber/fiber/releases/tag/v2.52.14","tags":["x_refsource_MISC"]},{"url":"https://github.com/gofiber/fiber/releases/tag/v3.3.0","name":"https://github.com/gofiber/fiber/releases/tag/v3.3.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-290","lang":"en","description":"CWE-290: Authentication Bypass by Spoofing","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-08T19:26:26.580Z"},"source":{"advisory":"GHSA-gcfq-8gqf-4876","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-09T13:19:42.395861Z","id":"CVE-2026-45045","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-09T13:20:08.367Z"}}]}}}