# CVE-2026-48761: Symfony: HtmlSanitizer UrlAttributeSanitizer Misses URL Attributes

> Attackers can inject JavaScript payloads via specific HTML tags in Symfony's HTML sanitizer, leading to cross-site scripting if those elements are explicitly enabled.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 14 Jul 2026
- **Updated:** 21 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-48761, GHSA-x5qj-865h-mgvm, UBUNTU-CVE-2026-48761

## What is CVE-2026-48761?

CVE-2026-48761 is a medium-severity cross-site scripting vulnerability in Sensiolabs Symfony, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0 until 6.4.41, 7.4.13, and 8.0.13, UrlAttributeSanitizer::getSupportedAttributes() omitted URL-bearing attributes on <object>, <applet>, <iframe>, and <img>, and <meta http-equiv="refresh"> URLs inside content bypassed URL sanitization, allowing explicitly enabled elements or attributes to pass javascript: and similar payloads into sanitized output. This issue is fixed in versions 6.4.41, 7.4.13, and 8.0.13.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-1023 (Incomplete Comparison with Missing Factors)

## Which versions are affected by CVE-2026-48761?

12 open source packages ship an affected version, including symfony/html-sanitizer and symfony/symfony. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `symfony/html-sanitizer` | Packagist | From 6.1.0 | 6.4.41 |
| `symfony/html-sanitizer` | Packagist | From 6.1.0 | 6.4.41 |
| `symfony/html-sanitizer` | Packagist | From 7.0.0 | 7.4.13 |
| `symfony/html-sanitizer` | Packagist | From 7.0.0 | 7.4.13 |
| `symfony/html-sanitizer` | Packagist | From 8.0.0 | 8.0.13 |
| `symfony/html-sanitizer` | Packagist | From 8.0.0 | 8.0.13 |
| `symfony/symfony` | Packagist | From 6.1.0 | 6.4.41 |
| `symfony/symfony` | Packagist | From 6.1.0 | 6.4.41 |
| `symfony/symfony` | Packagist | From 7.0.0 | 7.4.13 |
| `symfony/symfony` | Packagist | From 7.0.0 | 7.4.13 |
| `symfony/symfony` | Packagist | From 8.0.0 | 8.0.13 |
| `symfony/symfony` | Packagist | From 8.0.0 | 8.0.13 |

Products: Sensiolabs Symfony.

## How do I fix CVE-2026-48761?

Upgrade symfony/html-sanitizer to a fixed version for your release line: 6.4.41, 7.4.13 or 8.0.13.

## Is CVE-2026-48761 being exploited?

There is no known exploitation of CVE-2026-48761 in the wild and no public exploit code.

## Other vulnerabilities in Sensiolabs Symfony

- [CVE-2019-11325](https://insights.sbomify.com/CVE-2019-11325/): Improper Input Validation in Symfony (critical 9.8)
- [CVE-2017-11365](https://insights.sbomify.com/CVE-2017-11365/): Symfony Incorrect Access Control (critical 9.8)
- [CVE-2019-10913](https://insights.sbomify.com/CVE-2019-10913/): Invalid HTTP method overrides allow possible XSS or other attacks in Symfony (critical 9.8)
- [CVE-2018-11407](https://insights.sbomify.com/CVE-2018-11407/): Symfony Authentication Bypass (critical 9.8)
- [CVE-2016-2403](https://insights.sbomify.com/CVE-2016-2403/): Symfony Authentication Bypass (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48761 and fix it if it is affected.

What it is: CVE-2026-48761 is a medium-severity cross-site scripting vulnerability in Sensiolabs Symfony, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-48761 in the wild and no public exploit code.

Affected packages and fixed versions:
- symfony/html-sanitizer (Packagist): affected from 6.1.0; fixed in 6.4.41
- symfony/html-sanitizer (Packagist): affected from 6.1.0; fixed in 6.4.41
- symfony/html-sanitizer (Packagist): affected from 7.0.0; fixed in 7.4.13
- symfony/html-sanitizer (Packagist): affected from 7.0.0; fixed in 7.4.13
- symfony/html-sanitizer (Packagist): affected from 8.0.0; fixed in 8.0.13
- symfony/html-sanitizer (Packagist): affected from 8.0.0; fixed in 8.0.13
- symfony/symfony (Packagist): affected from 6.1.0; fixed in 6.4.41
- symfony/symfony (Packagist): affected from 6.1.0; fixed in 6.4.41
- symfony/symfony (Packagist): affected from 7.0.0; fixed in 7.4.13
- symfony/symfony (Packagist): affected from 7.0.0; fixed in 7.4.13
- symfony/symfony (Packagist): affected from 8.0.0; fixed in 8.0.13
- symfony/symfony (Packagist): affected from 8.0.0; fixed in 8.0.13

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-48761/ (Markdown: https://insights.sbomify.com/CVE-2026-48761/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48761
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48761
- OSV: https://osv.dev/vulnerability/CVE-2026-48761

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48761/
Summaries are generated and may contain mistakes; the official description above is the record.