CVE-2026-45064: HtmlSanitizer URL Attributes Pass Through BiDi Override Characters → Visual href Spoofing

Published May 20, 2026
·
Updated

Description

Symfony\Component\HtmlSanitizer\TextSanitizer\UrlSanitizer::parse() (used by UrlSanitizer::sanitize() and therefore by every HtmlSanitizer config that allows links or media) accepts URLs that contain Unicode explicit-direction BiDi formatting characters: U+202A–U+202E (LRE / RLE / PDF / LRO / RLO) and U+2066–U+2069 (LRI / RLI / FSI / PDI). These characters are passed through unchanged into the href / src attributes produced by HtmlSanitizer. When the resulting HTML is rendered in a browser, the override characters reverse or alter the visual ordering of the URL text, so the displayed link can differ arbitrarily from the actual destination: a classic visual-spoofing / phishing primitive against viewers of sanitized content.

Resolution

UrlSanitizer::parse() now rejects URLs containing the explicit-direction BiDi formatting code points (U+202A–U+202E, U+2066–U+2069) before invoking the underlying URL parser. As an unrelated companion fix in the same patch, spaces inside path/query/fragment are now percent-encoded rather than rejected outright, while spaces in the scheme/authority remain rejected by the post-encoding whitespace check.

The patch for this issue is available here for branch 5.4.

Credits

Symfony would like to thank Himanshu Anand for reporting the issue and Nicolas Grekas for providing the fix.

Other sources

CVE-2026-45064: HtmlSanitizer URL Attributes Pass Through BiDi Override Characters → Visual href Spoofing

— Packagist

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, UrlSanitizer::parse() passes Unicode explicit-direction BiDi formatting characters through into sanitized href and src attributes, allowing sanitized content to display a link destination that visually differs from the actual destination and enabling phishing-style visual spoofing. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.

— MITRE

Affected Software

30 affected componentsFixes available
composer/symfony/symfony>=8.0.0<8.0.12
8.0.12
composer/symfony/symfony>=7.0.0<7.4.12
7.4.12
composer/symfony/symfony>=6.1.0<6.4.40
6.4.40
composer/symfony/html-sanitizer>=8.0.0<8.0.12
8.0.12
composer/symfony/html-sanitizer>=7.0.0<7.4.12
7.4.12
composer/symfony/html-sanitizer>=6.1.0<6.4.40
6.4.40
SensioLabs Symfony>=6.1.0<6.4.40
SensioLabs Symfony>=7.0.0<7.4.12
SensioLabs Symfony>=8.0.0<8.0.12
composer/symfony/symfony>=6.1.0, <6.2.0
composer/symfony/symfony>=6.2.0, <6.3.0
composer/symfony/symfony>=6.3.0, <6.4.0
composer/symfony/symfony>=6.4.0, <6.4.40
6.4.40
composer/symfony/symfony>=7.0.0, <7.1.0
composer/symfony/symfony>=7.1.0, <7.2.0
composer/symfony/symfony>=7.2.0, <7.3.0
composer/symfony/symfony>=7.3.0, <7.4.0
composer/symfony/symfony>=7.4.0, <7.4.12
7.4.12
composer/symfony/symfony>=8.0.0, <8.0.12
8.0.12
composer/symfony/html-sanitizer>=6.1.0, <6.2.0
composer/symfony/html-sanitizer>=6.2.0, <6.3.0
composer/symfony/html-sanitizer>=6.3.0, <6.4.0
composer/symfony/html-sanitizer>=6.4.0, <6.4.40
6.4.40
composer/symfony/html-sanitizer>=7.0.0, <7.1.0
composer/symfony/html-sanitizer>=7.1.0, <7.2.0
composer/symfony/html-sanitizer>=7.2.0, <7.3.0
composer/symfony/html-sanitizer>=7.3.0, <7.4.0
composer/symfony/html-sanitizer>=7.4.0, <7.4.12
7.4.12
composer/symfony/html-sanitizer>=8.0.0, <8.0.12
8.0.12
debian/symfony
5.4.53+dfsg-0+deb12u16.4.41+dfsg-0+deb13u16.4.49+dfsg-0+deb13u17.4.22+dfsg-17.4.23+dfsg-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade composer/symfony/symfony to a version that resolves this vulnerability.

    Fixed in 8.0.12
  2. Upgrade

    Upgrade composer/symfony/symfony to a version that resolves this vulnerability.

    Fixed in 7.4.12
  3. Upgrade

    Upgrade composer/symfony/symfony to a version that resolves this vulnerability.

    Fixed in 6.4.40
  4. Upgrade

    Upgrade composer/symfony/html-sanitizer to a version that resolves this vulnerability.

    Fixed in 8.0.12
  5. Upgrade

    Upgrade composer/symfony/html-sanitizer to a version that resolves this vulnerability.

    Fixed in 7.4.12
  6. Upgrade

    Upgrade composer/symfony/html-sanitizer to a version that resolves this vulnerability.

    Fixed in 6.4.40
  7. Upgrade

    Upgrade debian/symfony to a version that resolves this vulnerability.

    Fixed in 5.4.53+dfsg-0+deb12u1Fixed in 6.4.41+dfsg-0+deb13u1Fixed in 6.4.49+dfsg-0+deb13u1Fixed in 7.4.22+dfsg-1Fixed in 7.4.23+dfsg-1
  8. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.4.40
  9. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 7.4.12
  10. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 8.0.12
  11. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Patch 743a435e948b897ef2b5564ac438d4beb95d2526

Event History

May 20, 2026
Advisory Published
via Packagist·08:00 AM
Data Sourced
via Packagist·08:00 AM
DescriptionSeverityAffected Software
May 27, 2026
Advisory Published
via GitHub·08:04 PM
Data Sourced
via GitHub·08:04 PM
DescriptionWeaknessAffected Software
Jul 14, 2026
CVE Published
via MITRE·06:35 PM
Data Sourced
via MITRE·06:35 PM
DescriptionWeakness
Data Sourced
via NVD·07:17 PM
RemedyDescriptionSeverityWeaknessAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is the severity of CVE-2026-45064?

The severity level of CVE-2026-45064 is rated at 37, indicating a moderate risk.

2

How do I fix CVE-2026-45064?

To mitigate CVE-2026-45064, update to the latest version of Symfony where the vulnerability has been patched.

3

What types of characters are exploited in CVE-2026-45064?

CVE-2026-45064 is exploited through Unicode explicit-direction BiDi formatting characters: U+202A to U+202E.

4

Which Symfony components are affected by CVE-2026-45064?

CVE-2026-45064 affects the Symfony component users of the HtmlSanitizer, particularly the UrlSanitizer class.

5

What impact does CVE-2026-45064 have on web applications?

CVE-2026-45064 can allow for potential injection attacks through improperly sanitized URLs in web applications.

Company

Resources

Contact

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