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SymfonyFramework / library · Sensiolabs

CVE-2026-45071

HIGH · 7.5 CVSS v3.1 Published 2026-07-14
Fix available
A fix is available. Upgrade to 5.4.52 / 6.4.40 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click 5 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Crawler::addXmlContent() set DOMDocument::$validateOnParse = true before loadXML(), re-enabling external entity resolution and allowing attacker-supplied XML to expand file:// entities such as local files. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Crawler::addXmlContent() method in Symfony sets DOMDocument::$validateOnParse = true before loadXML(), which re-enables XML external entity (XXE) processing disabled by default in PHP 8.0+. This allows attacker-supplied XML with file:// URI entities to read local files from the server.

MitigationUpgrade Symfony to version 5.4.52, 6.4.40, 7.4.12, 8.0.12 or later. If immediate upgrade is not feasible, avoid passing untrusted XML input to Crawler::addXmlContent().

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
SymfonyFramework / library
Affected:< 5.4.52>= 6.0.0, < 6.4.40>= 7.0.0, < 7.4.12>= 8.0.0, < 8.0.12

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Symfony Crawler usage
    Search your codebase for 'use Symfony\DomCrawler\Crawler' or 'new Crawler' statements to confirm the Symfony DomCrawler component is in use.
    Affected if The Symfony DomCrawler component is not present in your codebase.
  2. Check installed Symfony version
    Run 'composer show symfony/dom-crawler' or check your composer.lock file for the symfony/dom-crawler package version.
    Affected if The installed version is < 5.4.52, >= 6.0.0 and < 6.4.40, >= 7.0.0 and < 7.4.12, or >= 8.0.0 and < 8.0.12.
  3. Check PHP version
    Run 'php -v' to determine the PHP version.
    Affected if PHP version is 8.0 or higher (the vulnerability relies on XXE being disabled by default in PHP 8.0+).
  4. Find addXmlContent usage
    Search your codebase for calls to 'addXmlContent()' method, particularly on Crawler instances. Look for patterns like '$crawler->addXmlContent($userInput)' or similar where the XML source could be attacker-controlled.
    Affected if Code passes untrusted or user-supplied XML input directly to Crawler::addXmlContent() without sanitization.

You are affected if your application runs on PHP 8.0+, uses Symfony DomCrawler with a version in the affected ranges, and passes untrusted XML input to the Crawler::addXmlContent() method.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.4.52 / 6.4.40 / 7.4.12 or later
Fixed in 5.4.526.4.407.4.12
Interim mitigation

Upgrade Symfony to version 5.4.52, 6.4.40, 7.4.12, 8.0.12 or later. If immediate upgrade is not feasible, avoid passing untrusted XML input to Crawler::addXmlContent().

Recommended fix High confidence

Upgrade to Symfony 5.4.52 (for 5.x), 6.4.40 (for 6.x), 7.4.12 (for 7.x), or 8.0.12 (for 8.x) depending on your current major version

  1. 1. Identify the current Symfony version by running `composer show symfony/framework-bundle` or checking composer.lock
  2. 2. Based on the current version, determine the appropriate upgrade target: for 5.x upgrade to 5.4.52; for 6.x upgrade to 6.4.40; for 7.x upgrade to 7.4.12; for 8.x upgrade to 8.0.12
  3. 3. Update the Symfony version in composer.json: `composer require symfony/framework-bundle:^5.4.52` (or ^6.4.40, ^7.4.12, ^8.0.12 depending on your branch)
  4. 4. Run `composer update symfony/framework-bundle --with-all-dependencies` to update Symfony and its dependencies
  5. 5. Verify the upgrade by running `composer show symfony/framework-bundle` to confirm the version
  6. 6. Run your application's test suite to ensure compatibility
  7. 7. Test the Crawler::addXmlContent() functionality to confirm the XXE vulnerability is fixed
Caveat Minor/patch upgrades typically have low breaking change risk, but review Symfony's changelog for your version branch for any deprecation notices or breaking changes before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Symfony Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-45071 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data