Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2026-45071 high CVSS 7.5

XXE (XML External Entity) in symfony/dom-crawler (CVE-2026-45071)

Summary

Vulnerability in symfony/dom-crawler (CVE-2026-45071). Confidential information can be exposed externally. Exploitable via Crawler. Mitigation: upgrade to 8.0.12 or later.

Original description

The description as published by the source.

Description

symfony/dom-crawler provides the Crawler class for navigating HTML/XML documents with CSS/XPath selectors; symfony/browser-kit's HttpBrowser uses it to parse fetched pages.

Crawler::addXmlContent() sets DOMDocument::$validateOnParse = true before calling loadXML(). Setting validateOnParse re-enables libxml's DTD subset processing, including external entity resolution, even though LIBXML_NONET is passed. LIBXML_NONET blocks network fetches but not file:// entities. An attacker-supplied XML document with a SYSTEM "file:///etc/passwd" entity is therefore expanded.

Resolution

The Crawler::addXmlContent method does not set the validateOnParse flag anymore.

The patch for this issue is available here for branch 5.4.

Credits

Symfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.

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-2026-45071 has been found in symfony/dom-crawler.
Attackers can target a specific entry point like Crawler over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: upgrade symfony/dom-crawler to 8.0.12 or later.
If unsure, ask your IT team or search "symfony/dom-crawler CVE-2026-45071" on the vendor's site.

CVE-2026-45071 (symfony/dom-crawler) — CWE-611 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Crawler / HttpBrowser / validateOnParse / LIBXML_NONET
Patched: 8.0.12 — 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-611) exists in symfony/dom-crawler. Attackers reach the vulnerable code path via Crawler without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of symfony/dom-crawler. Attack surface: Crawler / HttpBrowser / validateOnParse / LIBXML_NONET.

🔥 Severity

Severity: High (CVSS 7.5/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 8.0.12.

🛡️ 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 'symfony/dom-crawler' . 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 'symfony/dom-crawler' . | 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 symfony/dom-crawler 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 symfony/dom-crawler to 8.0.12

    ステージング環境で 8.0.12 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 symfony/dom-crawler
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.0.12"}]}]
composer symfony/symfony
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.0.12"}]}]
Packagist symfony/dom-crawler
[{"type":"ECOSYSTEM","events":[{"introduced":"8.0.0"},{"fixed":"8.0.12"}]}]
Packagist symfony/symfony
[{"type":"ECOSYSTEM","events":[{"introduced":"8.0.0"},{"fixed":"8.0.12"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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