Vulnerability in github.com/caddyserver/caddy/v2 (CVE-2026-45692)
Summary
Vulnerability in github.com/caddyserver/caddy/v2 (CVE-2026-45692). Risk of unauthorized operations or information disclosure. Exploitable via GET /config/apps/http/servers/srv/routes/0. Mitigation: upgrade to 2.11.3 or later.
Original description
The description as published by the source.
This report is not about a normal textual prefix-expansion case.
The issue here is that the authorization layer and the /config traversal layer do not agree on what object the path refers to.
In this case, a path authorized for one config object is accepted, but then resolves to a different config object during traversal.
AI Disclosure
The reporter used an LLM to help review the code, reason about the behavior, and help draft this report.
The reporter manually reproduced and validated the issue locally, confirmed the relevant source paths, and captured the requests and responses below.
Summary
A remote admin client certificate restricted to the following path:
/config/apps/http/servers/srv/routes/0
can still read and modify a different array element by requesting:
/config/apps/http/servers/srv/routes/01
This happens because:
- the authorization layer uses string prefix matching
- the /config traversal layer parses array indices numerically using strconv.Atoi()
So:
- authorization sees /.../01 as matching /.../0
- traversal resolves 01 to numeric index 1
- the request therefore targets routes[1], not routes[0]
This is not just a prefix-match quirk. It is an authorization-to-object mismatch.
Why This Is In Scope
This is a security bug in Caddy's own code:
- no browser behavior is involved
- no dependency bug is involved
- no external system compromise is involved
- no third-party so…
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-2026-45692 has been found in github.com/caddyserver/caddy/v2.
Attackers can target a specific entry point like GET /config/apps/http/servers/srv/routes/0 over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.4/10.
What to do: upgrade github.com/caddyserver/caddy/v2 to 2.11.3 or later.
If unsure, ask your IT team or search "github.com/caddyserver/caddy/v2 CVE-2026-45692" on the vendor's site.
CVE-2026-45692 (github.com/caddyserver/caddy/v2) — CWE-187 / CVSS v3 5.4
Attack vector: remote (network-reachable) / no user interaction
Attack surface: GET /config/apps/http/servers/srv/routes/0 / GET /config/apps/http/servers/srv/routes/01 / GET /config/apps/http/servers/srv/routes/02 / PATCH /config/apps/http/servers/srv/routes/01
Patched: 2.11.3 — 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-187) exists in github.com/caddyserver/caddy/v2. Attackers reach the vulnerable code path via GET /config/apps/http/servers/srv/routes/0.
Check the vendor advisory for the affected versions of github.com/caddyserver/caddy/v2. Attack surface: GET /config/apps/http/servers/srv/routes/0 / GET /config/apps/http/servers/srv/routes/01 / GET /config/apps/http/servers/srv/routes/02 / PATCH /config/apps/http/servers/srv/routes/01.
Severity: Medium (CVSS 5.4/10). Risk of unauthorized operations or information disclosure.
Update to 2.11.3.
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 /config/apps/http/servers/srv/routes/0 requests with malformed payloads or SQL meta-characters. Run grep -r 'github.com/caddyserver/caddy/v2' . 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/caddyserver/caddy/v2' . | 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/caddyserver/caddy/v2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 /config/apps/http/servers/srv/routes/0' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /config/apps/http/servers/srv/routes/0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/caddyserver/caddy/v2 to 2.11.3ステージング環境で 2.11.3 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 /config/apps/http/servers/srv/routes/0 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
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Ubuntu UBUNTU-CVE-2026-45692 caddy
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com