Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2026-55824 low CVSS 2.6

Information Disclosure in contao/contao (CVE-2026-55824)

Summary

Vulnerability in contao/contao (CVE-2026-55824). Risk of unauthorized operations or information disclosure. Exploitable via Cookie. Mitigation: upgrade to 5.7.7 or later.

Original description

The description as published by the source.

Summary

Contao's crawler tries to prevent confidential HTTP client options from being sent to external domains by creating a scoped client: full options for root page origins, cleaned options for everything else. The cleaner removes Cookie and Authorization headers, but it removes the non-Symfony option names basic_auth and bearer_auth instead of Symfony HttpClient's real auth_basic and auth_bearer options.

When contao.crawl.default_http_client_options contains Basic or Bearer authentication for a protected staging/production site, those credentials remain in the "clean" client used for external links or configured additional URIs. An attacker who can get an external URL crawled, for example through a link on a crawled page while the broken-link checker is enabled, can receive the crawler credentials.

Technical Detail

Root Cause

// core-bundle/src/Crawl/Escargot/Factory.php:175-209 @ e550b92a01ef625bd546e6c3956dd200af05ebf0
private function createHttpClient(array $options = []): HttpClientInterface
{
    $options = array_merge_recursive(
        [
            'headers' => [
                'accept' => 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
                'user-agent' => self::USER_AGENT,
            ],
            'max_duration' => 10,
        ],
        array_merge_recursive($this->getDefaultHttpClientOptions(), $options),
    );

    $cleanOptions = $this->cleanOptionsFromConfidentialData($options);

    if ($…

Source: NIST National Vulnerability Database 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-2026-55824 has been found in contao/contao.
Attackers can target a specific entry point like Cookie over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 2.6/10.
What to do: upgrade contao/contao to 5.7.7 or later.
If unsure, ask your IT team or search "contao/contao CVE-2026-55824" on the vendor's site.

CVE-2026-55824 (contao/contao) — CWE-200 / CVSS v3 2.6
Attack vector: remote (network-reachable)
Attack surface: Cookie / Authorization / basic_auth / bearer_auth
Patched: 5.7.7 — 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

Information disclosure (CWE-200) exists in contao/contao. Attackers reach the vulnerable code path via Cookie.

📍 Affected scope

Check the vendor advisory for the affected versions of contao/contao. Attack surface: Cookie / Authorization / basic_auth / bearer_auth.

🔥 Severity

Severity: Low (CVSS 2.6/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 5.7.7.

🛡️ 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 'contao/contao' . 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 'contao/contao' . | 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 contao/contao 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 contao/contao to 5.7.7

    ステージング環境で 5.7.7 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 contao/contao
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.7.7"}]}]
composer contao/core-bundle
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.7.7"}]}]
Packagist contao/contao
[{"type":"ECOSYSTEM","events":[{"introduced":"5.4.0"},{"fixed":"5.7.7"}]}]
Packagist contao/core-bundle
[{"type":"ECOSYSTEM","events":[{"introduced":"5.4.0"},{"fixed":"5.7.7"}]}]

References

We use cookies for analytics and ad measurement. This setting applies to all Game co., Ltd. sites. Details