Vulnerability in github.com/vouch/vouch-proxy (CVE-2026-55149)
Summary
Vulnerability in github.com/vouch/vouch-proxy (CVE-2026-55149). Risk of unauthorized operations or information disclosure. Exploitable via GET /validate. Mitigation: upgrade to 0.48.0 or later.
Original description
The description as published by the source.
Unbounded Multipart Cookie Allocation DoS in vouch-proxy
Summary
vouch-proxy v0.47.2 contains an unauthenticated remote denial-of-service vulnerability in its multipart cookie reassembly logic. The /validate endpoint parses the total cookie part count directly from the attacker-controlled cookie name (e.g., VouchCookie_1of) and passes it without any bounds check to make([]string, N). A single HTTP request with N=10000000000 causes the Go runtime to attempt a ~160 GB heap allocation, triggering a fatal out-of-memory error that crashes the server process immediately. No authentication or prior session is required.
Details
The vulnerability exists in pkg/cookie/cookie.go. The Cookie() function iterates over all cookies in the request, identifies multipart cookies by the _NofM suffix in their name, and initializes the reassembly slice on the first matching cookie:
// pkg/cookie/cookie.go:123–130
xOFy := strings.Replace(cookie.Name, cookieUnder, "", 1)
xyArray := strings.Split(xOFy, "of")
if numParts == -1 {
if numParts, err = strconv.Atoi(xyArray[1]); err != nil {
return "", fmt.Errorf("multipart cookie fail: %s", err)
}
cookieParts = make([]string, numParts) // sink: unbounded allocation
}
The value in xyArray[1] comes directly from the cookie name supplied by the client. There is no maximum value check, no positive-range assertion, and no format validation before strconv.Atoi parses it. The result is used as the…
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-2026-55149 has been found in github.com/vouch/vouch-proxy.
Attackers can target a specific entry point like GET /validate over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade github.com/vouch/vouch-proxy to 0.48.0 or later.
If unsure, ask your IT team or search "github.com/vouch/vouch-proxy CVE-2026-55149" on the vendor's site.
CVE-2026-55149 (github.com/vouch/vouch-proxy) — CWE-789 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: GET /validate / _NofM / strconv.Atoi / make
Patched: 0.48.0 — 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.
A vulnerability (CWE-789) exists in github.com/vouch/vouch-proxy. Attackers reach the vulnerable code path via GET /validate without authentication.
Check the vendor advisory for the affected versions of github.com/vouch/vouch-proxy. Attack surface: GET /validate / _NofM / strconv.Atoi / make.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 0.48.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /validate requests with malformed payloads or SQL meta-characters. Run grep -r 'github.com/vouch/vouch-proxy' . 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/vouch/vouch-proxy' . | 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/vouch/vouch-proxyを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /validate' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /validateへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade github.com/vouch/vouch-proxy to 0.48.0ステージング環境で 0.48.0 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と、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against GET /validate on staging to confirm patch closes the vector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 Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com