CVE-2026-48761

Analyzed Analyzed - Analysis Complete

Stored XSS in Symfony Framework via Unsanitized URL Attributes

Publication date: 2026-07-14

Last updated on: 2026-07-21

Assigner: GitHub, Inc.

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-07-14

Last Modified

2026-07-21

Generated

2026-08-04

AI Q&A

2026-07-15

EPSS Evaluated

2026-08-02

NVD

CVE-2026-48761

Affected Vendors & Products

Vendor	Product	Version / Range
sensiolabs	symfony	From 7.0.0 (inc) to 7.4.13 (exc)
sensiolabs	symfony	From 8.0.0 (inc) to 8.0.13 (exc)
sensiolabs	symfony	From 6.1.0 (inc) to 6.4.41 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CWE-1023	The product performs a comparison between entities that must consider multiple factors or characteristics of each entity, but the comparison does not include one or more of these factors.

Attack-Flow Graph

Executive Summary

This vulnerability affects Symfony, a PHP framework, where the UrlAttributeSanitizer failed to properly sanitize URL-bearing attributes on specific HTML elements like object, applet, iframe, img, and meta tags. This allowed malicious javascript: and similar payloads to bypass sanitization and be included in output.

Detection Guidance

Detecting this vulnerability requires checking Symfony versions and inspecting sanitized HTML output for unsanitized javascript: or similar payloads in URL attributes. Use commands like 'composer show symfony/symfony' to check installed versions. Review application logs for suspicious URL patterns in sanitized content.

Impact Analysis

An attacker could exploit this to inject malicious scripts into web pages, potentially leading to cross-site scripting (XSS) attacks. This could allow unauthorized access to user sessions, data theft, or defacement of websites using affected Symfony versions.

Compliance Impact

This vulnerability could lead to data breaches, violating GDPR's data protection requirements and HIPAA's security rules for protected health information. Organizations may face fines or penalties for failing to protect user data due to inadequate sanitization.

Mitigation Strategies

Upgrade Symfony to versions 6.4.41, 7.4.13, or 8.0.13 or later. If upgrading is not possible, review and manually sanitize HTML output to ensure URL attributes on <object>, <applet>, <iframe>, <img>, and <meta http-equiv="refresh"> are properly sanitized.

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