CVE-2026-48761 Symfony: HtmlSanitizer UrlAttributeSanitizer Misses URL Attributes
Attackers can inject JavaScript payloads via specific HTML tags in Symfony's HTML sanitizer, leading to cross-site scripting if those elements are explicitly enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-48761?
CVE-2026-48761 is a medium-severity cross-site scripting vulnerability in Sensiolabs Symfony, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Which versions are affected by CVE-2026-48761?
12 open source packages ship an affected version, including symfony/html-sanitizer and symfony/symfony. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
symfony/html-sanitizer Packagist | From 6.1.0 | 6.4.41 |
symfony/html-sanitizer Packagist | From 6.1.0 | 6.4.41 |
symfony/html-sanitizer Packagist | From 7.0.0 | 7.4.13 |
symfony/html-sanitizer Packagist | From 7.0.0 | 7.4.13 |
symfony/html-sanitizer Packagist | From 8.0.0 | 8.0.13 |
symfony/html-sanitizer Packagist | From 8.0.0 | 8.0.13 |
6 more packages
symfony/symfony Packagist | From 6.1.0 | 6.4.41 |
symfony/symfony Packagist | From 6.1.0 | 6.4.41 |
symfony/symfony Packagist | From 7.0.0 | 7.4.13 |
symfony/symfony Packagist | From 7.0.0 | 7.4.13 |
symfony/symfony Packagist | From 8.0.0 | 8.0.13 |
symfony/symfony Packagist | From 8.0.0 | 8.0.13 |
Products include Sensiolabs Symfony.
How do I fix CVE-2026-48761?
Upgrade symfony/html-sanitizer to a fixed version for your release line: 6.4.41, 7.4.13 or 8.0.13.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-48761 being exploited?
There is no known exploitation of CVE-2026-48761 in the wild and no public exploit code.
Other vulnerabilities in Sensiolabs Symfony
Sources
Also known as DEBIAN-CVE-2026-48761, GHSA-x5qj-865h-mgvm, UBUNTU-CVE-2026-48761.