CVE-2026-45753 json
Symfony: HtmlSanitizer UrlAttributeSanitizer Omits action/formaction/poster/cite — javascript: URI Survives Sanitization (XSS)
published 2026-05-28 5 mo ago modified 2026-09-10 1 mo ago also GHSA-hhg7-c65m-h7ff , EUVD-2026-44344
- cvss
- 6.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 16%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- packagist symfony/html-sanitizer 6.4.40, 7.4.12, 8.0.12
- packagist symfony/symfony 6.4.40, 7.4.12, 8.0.12
- sensiolabs symfony 6.4.40, 7.4.12, 8.0.12
- symfony Debian 13 6.4.41+dfsg-0+deb13u1
- symfony Debian 14 7.4.12+dfsg-1
debian advisories DEBIAN-CVE-2026-45753
- github.com/symfony/symfony@487728e commit
- github.com/symfony/symfony@26a598f commit
- github.com/symfony/symfony/releases/tag/v6.4.40 release
- github.com/symfony/symfony/releases/tag/v7.4.12 release
- github.com/symfony/symfony/releases/tag/v8.0.12 release
- github.com/symfony/symfony/security/advisories/GHSA-hhg7-c65m-h7ff advisory
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 2.1 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N |
| CNA | 4.0 | 2.1 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| packagist | symfony/html-sanitizer | >=6.1.0, <6.4.40 >=7.0.0, <7.4.12 >=8.0.0, <8.0.12 |
6.4.40 7.4.12 8.0.12 |
| packagist | symfony/symfony | >=6.1.0, <6.4.40 >=7.0.0, <7.4.12 >=8.0.0, <8.0.12 |
6.4.40 7.4.12 8.0.12 |
Affected products
- symfony symfony
- symfony html-sanitizer
Classification
References
-
github.com
/symfony/symfony/commit/487728e7e180a674a6d4c01bd0cb56161cc441b7
patch
-
github.com
/symfony/symfony/security/advisories/GHSA-hhg7-c65m-h7ff
web, patch, vendor-advisory
-
github.com
/symfony/symfony/commit/26a598fcfc4f903cc55ff202f642ee621839825e
web
-
github.com
/symfony/symfony/releases/tag/v6.4.40
product, release-notes
-
github.com
/symfony/symfony/releases/tag/v7.4.12
product, release-notes
-
github.com
/symfony/symfony/releases/tag/v8.0.12
product, release-notes
-
github.com
/FriendsOfPHP/security-advisories/blob/master/symfony/html-sanitizer/CVE-2026-45753.yaml
web
-
github.com
/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-45753.yaml
web
-
github.com
/symfony/symfony
package
-
symfony.com
/cve-2026-45753
web
Sources
- CVE List CVE-2026-45753
- GitHub Advisory GHSA-hhg7-c65m-h7ff
- NVD CVE-2026-45753
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