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.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-290"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45045.json"
}{
"extracted_events": [
{
"cpe": "cpe:2.3:a:gofiber:fiber:*:*:*:*:*:go:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "2.52.14"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:gofiber:fiber:*:*:*:*:*:go:*:*",
"range": [
{
"introduced": "3.0.0"
},
{
"fixed": "3.3.0"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "1403cc8292da3220e9316960b4030cc722a0f396"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "33c9501288ab47a429c8b5e701493f0c3c0af37d"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "v2.52.14",
"range": [
{
"fixed": "a74500f6335abc020023d3581a46ba56a893edc3"
}
],
"source": "REFERENCES_TAG"
},
{
"original_tag": "v3.3.0",
"range": [
{
"fixed": "a39a035dee6df089d94f4f78e34dd34dac895aee"
}
],
"source": "REFERENCES_TAG"
}
]
}