Symfony: HtmlSanitizer URL Parser Deny Gates Underinclusive: Percent-Encoded BiDi Marks and Unicode Whitespace Bypass Visual-Spoofing Defense

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

• CVE-2026-48760: 0.34% estimated exploitation activity in the next 30 days; percentile 27.27 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Description Symfony\Component\HtmlSanitizer\TextSanitizer\UrlSanitizer::parse() rejects URLs containing raw Unicode explicit-direction BiDi formatting characters (U+202A–U+202E, U+2066–U+2069) as a defense against visual-spoofing of the rendered href. The check covers only the raw UTF-8 forms of those code points: the percent-encoded forms (%E2%80%AE for U+202E, %E2%81%A6 for U+2066, etc.) are not matched by the deny regex, survive league/uri's parse/build cycle, and are re-emitted unchanged in the sanitized URL. Any downstream consumer that decodes the link before display — phishing-detection filters that compare urldecode($href) against a domain allow-list, audit-log dashboards that show a decoded form for readability, hover-tooltip previews, federated/syndicated content where the decoder lives on the consuming side — restores the BiDi character and the visual spoof that the original defense was filed to prevent. The same UrlSanitizer::parse() carries an ASCII-only /\s/ whitespace…

Published by the source

15 Jun 2026, 17:32 UTC

Last modified by the source

15 Jun 2026, 17:32 UTC

Source last checked

26 Oct 2026, 14:49 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-v3wm-qf9p-c549

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# Patch Next advisory brief: CVE-2026-48760

Advisory: Symfony: HtmlSanitizer URL Parser Deny Gates Underinclusive: Percent-Encoded BiDi Marks and Unicode Whitespace Bypass Visual-Spoofing Defense
IDs: CVE-2026-48760, GHSA-v3wm-qf9p-c549
Record: https://patchnext.com/advisories/cve-2026-48760 (revision 1, source checked 26 Oct 2026, 14:49 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: symfony/symfony 8.0.13, 7.4.13, 6.4.41; symfony/html-sanitizer 8.0.13, 7.4.13, 6.4.41. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist symfony/symfony: affected >= 6.1.0, < 6.4.41; >= 7.0.0, < 7.4.13; >= 8.0.0, < 8.0.13; fixed in 6.4.41, 8.0.13, 7.4.13
- Packagist symfony/html-sanitizer: affected >= 6.1.0, < 6.4.41; >= 7.0.0, < 7.4.13; >= 8.0.0, < 8.0.13; fixed in 6.4.41, 8.0.13, 7.4.13

## Suggested inspection (read-only)
- Packagist symfony/symfony: check the installed version with your package manager.
- Packagist symfony/html-sanitizer: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on symfony/symfony, symfony/html-sanitizer.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-v3wm-qf9p-c549 (GitHub-reviewed advisory GHSA-v3wm-qf9p-c549 lists affected ranges: Packagist symfony/html-sanitizer >=6.1.0 =7.0.0 =8.0.0 =6.1.0 =7.0.0 =8.0.0 <8.0.13)

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