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CVE-2026-35445

Vulnerability in winter/wn-backend-module (CVE-2026-35445)

Summary

Vulnerability in winter/wn-backend-module (CVE-2026-35445). Risk of unauthorized operations or information disclosure. Exploitable via _handler. Mitigation: upgrade to 1.2.13 or later.

Original description

The description as published by the source.

Impact

Affected versions of Winter CMS did not validate the handler name submitted through the form postback mechanism (_handler POST field) in the same way as AJAX requests (X_WINTER_REQUEST_HANDLER header). The AJAX path validates that handler names match the on[A-Z][\w+]* pattern, but the postback path passed the handler name directly to the handler dispatcher with no validation.

This allowed an authenticated backend user to call any method on a controller — including action-prefixed, protected, and private methods — by submitting a crafted POST request with a _handler field, as long as the controller either:

  • Contains a publicly available action via the $publicActions property, or
  • Degrades or removes the $requiredPermissions check in its constructor based on a condition

The backend's own Users controller was affected by the second scenario: it set $requiredPermissions to null for the myaccount action, allowing any authenticated backend user to access the controller without the backend.manage_users permission. Combined with the postback bypass, this allowed calling controller methods such as update_onDelete, update_onRestore, update_onUnsuspendUser, and update_onManualPasswordReset with attacker-controlled parameters.

Note that CSRF tokens are still verified on all POST requests, so the attacker must be logged into the backend with a valid session.

To actively exploit this security issue, an attacker would need access to the Backend…

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-2026-35445 has been found in winter/wn-backend-module.
Attackers can target a specific entry point like _handler over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade winter/wn-backend-module to 1.2.13 or later.
If unsure, ask your IT team or search "winter/wn-backend-module CVE-2026-35445" on the vendor's site.

CVE-2026-35445 (winter/wn-backend-module) — CWE-285
Attack surface: _handler / X_WINTER_REQUEST_HANDLER / null / myaccount
Patched: 1.2.13 — 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.

❓ What is the problem

A vulnerability (CWE-285) exists in winter/wn-backend-module. Attackers reach the vulnerable code path via _handler.

📍 Affected scope

Check the vendor advisory for the affected versions of winter/wn-backend-module. Attack surface: _handler / X_WINTER_REQUEST_HANDLER / null / myaccount.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1.2.13.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'winter/wn-backend-module' . 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

  1. 1
    Identify exposure identify 
    grep -r 'winter/wn-backend-module' . | 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 winter/wn-backend-module を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade winter/wn-backend-module to 1.2.13

    ステージング環境で 1.2.13 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。

  3. 3
    Post-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

composer winter/wn-backend-module
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.13"}]}]
Packagist winter/wn-backend-module
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.13"}]}]

References

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