Information Disclosure in github.com/gofiber/fiber/v3 (CVE-2026-30246)
Summary
Vulnerability in github.com/gofiber/fiber/v3 (CVE-2026-30246). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 3.2.0 or later.
Original description
The description as published by the source.
Summary
Fiber cache middleware's default key generator uses only c.Path() and does not include the query string.
As a result, requests like /?id=1 and /?id=2 can map to the same cache key and share the same cached response.
This can cause response mix-up (cache poisoning-like behavior) for endpoints where response content depends on query parameters.
Details
Default configuration in cache middleware:
KeyGenerator: func(c fiber.Ctx) string { return utils.CopyString(c.Path()) }
References:
- https://github.com/gofiber/fiber/blob/main/middleware/cache/config.go#L90-L92
- https://github.com/gofiber/fiber/blob/main/middleware/cache/cache_test.go#L599-L621
The existing test demonstrates that when handler output depends on query parameter id, a second request with a different query still returns the first cached response (cache hit), confirming query is not part of the default cache key.
PoC
Minimal PoC:
package main
import (
"log"
"github.com/gofiber/fiber/v3"
"github.com/gofiber/fiber/v3/middleware/cache"
)
func main() {
app := fiber.New()
app.Use(cache.New()) // default config
app.Get("/", func(c fiber.Ctx) error {
return c.SendString(c.Query("id", "1"))
})
log.Fatal(app.Listen(":3000"))
}
Reproduction:
GET /?id=1- Cache miss
- Response body:
1
GET /?id=2- Cache hit
- Response body:
1(expected2)
Local verification command used:
go test ./middleware/cac…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-30246 has been found in github.com/gofiber/fiber/v3.
Risk of unauthorized operations or information disclosure. CVSS score: 6.5/10.
What to do: upgrade github.com/gofiber/fiber/v3 to 3.2.0 or later.
If unsure, ask your IT team or search "github.com/gofiber/fiber/v3 CVE-2026-30246" on the vendor's site.
CVE-2026-30246 (github.com/gofiber/fiber/v3) — CWE-200 / CVSS v3 6.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 3.2.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Information disclosure (CWE-200) exists in github.com/gofiber/fiber/v3.
Check the vendor advisory for the affected versions of github.com/gofiber/fiber/v3.
Severity: Medium (CVSS 6.5/10). Risk of unauthorized operations or information disclosure.
Update to 3.2.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/gofiber/fiber/v3' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/gofiber/fiber/v3' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/gofiber/fiber/v3を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade github.com/gofiber/fiber/v3 to 3.2.0ステージング環境で 3.2.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com