Open Zaak is a modern, open-source data- and services-layer… (CVE-2020-26251)

Summary

Vulnerability reported (CVE-2020-26251). Risk of unauthorized operations or information disclosure. Exploitable via false.

Original description

The description as published by the source.

Open Zaak is a modern, open-source data- and services-layer to enable zaakgericht werken, a Dutch approach to case management. In Open Zaak before version 1.3.3 the Cross-Origin-Resource-Sharing policy in Open Zaak is currently wide open - every client is allowed. This allows evil.com to run scripts that perform AJAX calls to known Open Zaak installations, and the browser will not block these. This was intended to only apply to development machines running on localhost/127.0.0.1. Open Zaak 1.3.3 disables CORS by default, while it can be opted-in through environment variables. The vulnerability does not actually seem exploitable because: a) The session cookie has a Same-Site: Lax policy which prevents it from being sent along in Cross-Origin requests. b) All pages that give access to (production) data are login-protected c) Access-Control-Allow-Credentials is set to false d) CSRF checks probably block the remote origin, since they're not explicitly added to the trusted allowlist.

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV

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-2020-26251 has been found.
Attackers can target a specific entry point like false over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "CVE-2020-26251" on the vendor's site.

CVE-2020-26251
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: false
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 (unclassified) has been reported. Attackers reach the vulnerable code path via false without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions. Attack surface: false.

🔥 Severity

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

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ 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. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
Audit SBOM/dependencies for affected components.
```
資産台帳・SBOM・依存マニフェストで影響コンポーネントを特定する。
2
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。

References

advisory github.com
advisory github.com
patch github.com