CVE-2026-45753

Symfony: HtmlSanitizer UrlAttributeSanitizer Omits action/formaction/poster/cite — javascript: URI Survives Sanitization (XSS)

MEDIUM

6.1

CVSS Score

Published: July 14, 2026 at 06:21 PM UTC

Updated: July 15, 2026 at 02:14 PM UTC

3 products affected across 2 vendorsSymfonySymfonyHtml Sanitizer

Using symfony by symfony?

Get instant alerts when new vulnerabilities affect symfony - before attackers find them.

Real-time alertsTrack your software stackFree plan available

Start Free Sign In

Severity

MEDIUM6.1

Exploit prediction

EPSS 0.3%

SSVC

No known exploit

Description

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, UrlAttributeSanitizer::getSupportedAttributes() omits URL-valued attributes including action, formaction, poster, and cite, so configurations that admit those attributes can leave javascript: URIs unsanitized and enable XSS when the resulting HTML is rendered or a victim submits a form or clicks a button. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Symfony · Sensiolabsdrupal

95%

6.1.0 ≤ v < 6.4.407.0.0 ≤ v < 7.4.128.0.0 ≤ v < 8.0.12

Affected range stops below 6.4.40, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.4.12, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.0.12, so it looks safe — our inference, not a vendor statement

Html Sanitizer · Symfony

60%

v < 6.4.40v < 7.4.12v < 8.0.12

Affected range stops below 6.4.40, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.4.12, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.0.12, so it looks safe — our inference, not a vendor statement

Symfony · Symfonycomposer

60%

v < 6.4.40v < 7.4.12v < 8.0.12

Affected range stops below 6.4.40, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.4.12, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.0.12, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (5)

x_refsource_CONFIRMPatchVendor Advisory

Source: cverecord

https://github.com/symfony/symfony/security/advisories/GHSA-hhg7-c65m-h7ff

x_refsource_MISCPatch

Source: cverecord

https://github.com/symfony/symfony/commit/487728e7e180a674a6d4c01bd0cb56161cc441b7

x_refsource_MISCProductRelease Notes

Source: cverecord

https://github.com/symfony/symfony/releases/tag/v6.4.40

x_refsource_MISCProductRelease Notes

Source: cverecord

https://github.com/symfony/symfony/releases/tag/v7.4.12

x_refsource_MISCProductRelease Notes

Source: cverecord

https://github.com/symfony/symfony/releases/tag/v8.0.12

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.1MEDIUM[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: REQUIRED
Scope: CHANGED
Confidentiality: LOW
Integrity: LOW
Availability: NONE

Vector?

Quick Info

StatusANALYZED

CWE

CWE-79CWE-184

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Create account Sign in

Free plan, no card