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SymfonyFramework / library · Sensiolabs

CVE-2026-48761

MEDIUM · 6.1 CVSS v3.1 Published 2026-07-14
Fix available
A fix is available. Upgrade to 6.4.41 / 7.4.13 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges 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. From 6.1.0 until 6.4.41, 7.4.13, and 8.0.13, UrlAttributeSanitizer::getSupportedAttributes() omitted URL-bearing attributes on <object>, <applet>, <iframe>, and <img>, and <meta http-equiv="refresh"> URLs inside content bypassed URL sanitization, allowing explicitly enabled elements or attributes to pass javascript: and similar payloads into sanitized output. This issue is fixed in versions 6.4.41, 7.4.13, and 8.0.13.

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 · moderate confidence

The UrlAttributeSanitizer::getSupportedAttributes() method in Symfony omitted URL-bearing attributes on <object>, <applet>, <iframe>, <img> elements and <meta http-equiv=refresh> URLs from sanitization. This allowed javascript: and similar XSS payloads to bypass URL sanitization when those elements or attributes were explicitly enabled in the sanitizer configuration.

MitigationUpgrade Symfony to versions 6.4.41, 7.4.13, or 8.0.13. Alternatively, apply secondary HTML sanitization to content containing these elements before passing to UrlAttributeSanitizer.

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:>= 6.1.0, < 6.4.41>= 7.0.0, < 7.4.13>= 8.0.0, < 8.0.13

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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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. Determine installed Symfony version
    Run 'composer show symfony/symfony' or check the version in your composer.json file under require -> symfony/symfony
    Affected if The version falls within 6.1.0 to 6.4.40, 7.0.0 to 7.4.12, or 8.0.0 to 8.0.12
  2. Locate HTML sanitizer configuration
    Search your Symfony config files (typically in config/packages/ or config/) for files containing HtmlSanitizer, UrlAttributeSanitizer, or sanitizer configuration blocks
    Affected if No sanitizer configuration found - the default sanitizer may not be in use, but a custom one could still be affected
  3. Check enabled tags in sanitizer config
    Inspect the sanitizer configuration for the 'tags' or 'elements' section. Look specifically for 'object', 'applet', 'iframe', 'img', or 'meta' tags being allowed
    Affected if Any of these tags (object, applet, iframe, img, meta with http-equiv=refresh) are explicitly enabled in the sanitizer configuration
  4. Check enabled attributes in sanitizer config
    Inspect the 'attributes' or 'attr' section of the sanitizer config for URL-bearing attributes on those elements, such as 'src', 'data', 'codebase', or custom URL attributes
    Affected if URL-bearing attributes are configured to be allowed on object, applet, iframe, img, or meta elements
  5. Verify sanitizer usage in code
    Search your codebase for usages of HtmlSanitizer, UrlAttributeSanitizer, or the 'html_sanitizer' service that process user-supplied HTML
    Affected if The sanitizer is being used to clean HTML content, particularly from untrusted sources

You are affected if your Symfony version is within the affected range AND your sanitizer configuration explicitly enables object, applet, iframe, img, or meta elements with URL-bearing attributes.

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 6.4.41 / 7.4.13 / 8.0.13 or later
Fixed in 6.4.417.4.138.0.13
Interim mitigation

Upgrade Symfony to versions 6.4.41, 7.4.13, or 8.0.13. Alternatively, apply secondary HTML sanitization to content containing these elements before passing to UrlAttributeSanitizer.

Recommended fix High confidence

Upgrade to Symfony 6.4.41, 7.4.13, or 8.0.13 depending on your current major version branch

  1. 1. Identify the current Symfony version by running: composer show symfony/framework-bundle or checking composer.lock
  2. 2. Create a backup of the current project, including composer.lock and all source code
  3. 3. Update Composer dependencies to the fixed version using: composer require symfony/framework-bundle:^6.4.41 (or ^7.4.13 or ^8.0.13 depending on your major version)
  4. 4. Alternatively, run: composer update symfony/framework-bundle --with-all-dependencies to update to the latest patch in the current major version, which should pull the fixed version
  5. 5. Clear Symfony cache: php bin/console cache:clear --env=prod (and dev if applicable)
  6. 6. Verify the upgrade by checking: composer show symfony/framework-bundle to confirm the installed version
  7. 7. Run existing test suites to ensure no regressions were introduced
  8. 8. Deploy to staging/QA environment and verify URL sanitization functions correctly
Caveat Patch releases (6.4.41, 7.4.13, 8.0.13) typically have minimal breaking changes; however, review Symfony's release notes for the specific version for any deprecation notices affecting your application

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

Fix this in Symfony Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
Get the upgrade done

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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-2026-48761 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