Symfony up to 6.4.39/7.4.11/8.0.11 HtmlSanitizer allowLinkHosts/allowMediaHosts Remote Code Execution

Summaryinfo

A vulnerability, which was classified as critical, has been found in Symfony up to 6.4.39/7.4.11/8.0.11. This affects the function allowLinkHosts/allowMediaHosts of the component HtmlSanitizer. This manipulation causes Remote Code Execution. The identification of this vulnerability is CVE-2026-45066. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability has been found in Symfony up to 6.4.39/7.4.11/8.0.11 and classified as critical. Affected by this vulnerability is the function allowLinkHosts/allowMediaHosts of the component HtmlSanitizer. The manipulation with an unknown input leads to a remote code execution vulnerability. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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, HtmlSanitizer URL sanitization can allow off-allowlist URLs through allowLinkHosts() or allowMediaHosts() because UrlSanitizer::parse() follows RFC 3986 while browsers follow WHATWG URL parsing, and because <area href> is checked against the media policy rather than the link policy. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-45066 since 05/08/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

Upgrading to version 6.4.40, 7.4.12 or 8.0.12 eliminates this vulnerability.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• Symfony

Version

• 6.4.0
• 6.4.1
• 6.4.2
• 6.4.3
• 6.4.4
• 6.4.5
• 6.4.6
• 6.4.7
• 6.4.8
• 6.4.9
• 6.4.10
• 6.4.11
• 6.4.12
• 6.4.13
• 6.4.14
• 6.4.15
• 6.4.16
• 6.4.17
• 6.4.18
• 6.4.19
• 6.4.20
• 6.4.21
• 6.4.22
• 6.4.23
• 6.4.24
• 6.4.25
• 6.4.26
• 6.4.27
• 6.4.28
• 6.4.29
• 6.4.30
• 6.4.31
• 6.4.32
• 6.4.33
• 6.4.34
• 6.4.35
• 6.4.36
• 6.4.37
• 6.4.38
• 6.4.39
• 7.4.0
• 7.4.1
• 7.4.2
• 7.4.3
• 7.4.4
• 7.4.5
• 7.4.6
• 7.4.7
• 7.4.8
• 7.4.9
• 7.4.10
• 7.4.11
• 8.0.0
• 8.0.1
• 8.0.2
• 8.0.3
• 8.0.4
• 8.0.5
• 8.0.6
• 8.0.7
• 8.0.8
• 8.0.9
• 8.0.10
• 8.0.11

License

• open-source

Website

• Product: https://github.com/symfony/symfony/

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