CVE-2026-48760: Symfony HtmlSanitizer visual spoofing via percent-encoded BiDi characters

CVE-2026-48760 · Severity: medium · CVSS 0 · Published 2026-07-14

Symfony, a popular framework for building PHP web applications, contains a flaw in its URL sanitization component. This component is responsible for cleaning user-provided links to ensure they are safe to display. An attacker could bypass these security checks to include hidden characters that visually spoof URLs, potentially leading users to malicious websites or facilitating phishing attacks.

Technologies: symfony/html-sanitizer (Packagist), symfony/symfony (Packagist), Symfony HtmlSanitizer. Vendors: Packagist, Symfony.

Quick answers

Is CVE-2026-48760 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-48760 being exploited in the wild.
How severe is CVE-2026-48760?
Medium severity, with a CVSS score of 0, published 14 July 2026.
Which products and versions are affected?
symfony/html-sanitizer (Packagist) ECOSYSTEM:introduced=6.1.0,fixed=6.4.41; symfony/symfony (Packagist) ECOSYSTEM:introduced=6.1.0,fixed=6.4.41; Symfony HtmlSanitizer >= 6.1.0, < 6.4.41; >= 7.0.0-BETA1, < 7.4.13; >= 8.0.0-BETA1, < 8.0.13, >= 6.1.0, < 6.4.41; >= 7.0.0, < 7.4.13; >= 8.0.0, < 8.0.13.
Is there a fix for CVE-2026-48760?
Yes. symfony/html-sanitizer (Packagist): upgrade to 6.4.41 or later; symfony/symfony (Packagist): upgrade to 6.4.41 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-48760 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-48760?
Check whether you run symfony/html-sanitizer (Packagist), symfony/symfony (Packagist) or Symfony HtmlSanitizer at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • symfony/html-sanitizer (Packagist): upgrade to 6.4.41 or later
    composer require symfony/html-sanitizer:^6.4.41
  • symfony/symfony (Packagist): upgrade to 6.4.41 or later
    composer require symfony/symfony:^6.4.41

Technical details

A vulnerability exists in the Symfony HtmlSanitizer component's UrlSanitizer::parse() method. While the parser was designed to reject raw Bidirectional (BiDi) formatting characters, it failed to account for percent-encoded versions of these characters. Additionally, the component utilized an ASCII-only whitespace check, failing to identify and strip Unicode whitespace characters. This allows an attacker to craft URLs that appear legitimate to a user but contain hidden or spoofed characters that downstream consumers (like browsers or other services) may decode or display differently. The issue is resolved by hardening the parser to reject percent-encoded BiDi marks and expanding whitespace detection to include Unicode characters.

Affected products

  • symfony symfony >= 6.1.0, < 6.4.41; >= 7.0.0-BETA1, < 7.4.13; >= 8.0.0-BETA1, < 8.0.13
  • symfony html-sanitizer >= 6.1.0, < 6.4.41; >= 7.0.0-BETA1, < 7.4.13; >= 8.0.0-BETA1, < 8.0.13

Identifiers

  • CVE-2026-48760
  • GHSA-v3wm-qf9p-c549

Timeline

  • 2026-05-27: patched: Fixed in versions 6.4.41, 7.4.13, and 8.0.13
  • 2026-07-14: advisory: Public advisory and CVE published

References

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