CVE-2026-45072 in Symfony Web Profiler
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.4.24 until 6.4.40, 7.4.12, and 8.0.12, the development profiler file_excerpt Twig filter escapes PHP files through highlight_string() but interpolates lines from non-PHP files directly into <code> elements, allowing stored XSS against a developer who opens an attacker-written file such as var/log/dev.log in the profiler. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.
Quick answer
Symfony should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- Symfony 6.4.24 before 6.4.40
- Symfony before 7.4.12
- Symfony before 8.0.12
Fixed versions
- 6.4.40
- 7.4.12
- 8.0.12
How to fix it
CVE-2026-45072 is a cross-site scripting issue in Symfony. Update from Symfony 6.4.24 before 6.4.40 to 6.4.40 or newer. Keep it simple: upgrade first, then test the normal user flow.
- Find every place where Symfony is installed or used.
- Upgrade Symfony to 6.4.40 or a newer fixed release from the vendor.
- If you cannot upgrade right away, limit access to the affected feature until the update is done.
- Restart or redeploy the service if the product needs it after the update.
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Verify the fix
- Confirm the installed version is 6.4.40 or newer.
- Run a normal login, admin, and user flow to make sure the site still works.
- Check logs for new errors after the update.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-45072?
Symfony versions listed as affected should be reviewed: Symfony 6.4.24 before 6.4.40, Symfony before 7.4.12, Symfony before 8.0.12.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.