CVE-2023-46734 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in symfony/twig-bridge. A fix is available for symfony/twig-bridge — see the affected versions and patch details below.
Symfony potential Cross-site Scripting vulnerabilities in CodeExtension filters
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-46734.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-46734 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
symfony/twig-bridge🐘symfony/twig-bridge🐘symfony/twig-bridge🐘symfony/symfony🐘symfony/symfony🐘symfony/symfonyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Starting in versions 2.0.0, 5.0.0, and 6.0.0 and prior to versions 4.4.51, 5.4.31, and 6.3.8, some Twig filters in CodeExtension use is_safe=html but don't actually ensure their input is safe. As of versions 4.4.51, 5.4.31, and 6.3.8, Symfony now escapes the output of the affected filters.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/twig-bridge | ≥ 2.0.0&&< 4.4.51 | 4.4.51composer require symfony/twig-bridge:^4.4.51 |
| 🐘Packagist | symfony/twig-bridge | ≥ 5.0.0&&< 5.4.31 | 5.4.31composer require symfony/twig-bridge:^5.4.31 |
| 🐘Packagist | symfony/twig-bridge | ≥ 6.0.0&&< 6.3.8 | 6.3.8composer require symfony/twig-bridge:^6.3.8 |
| 🐘Packagist | symfony/symfony | ≥ 2.0.0&&< 4.4.51 | 4.4.51composer require symfony/symfony:^4.4.51 |
| 🐘Packagist | symfony/symfony | ≥ 5.0.0&&< 5.4.31 | 5.4.31composer require symfony/symfony:^5.4.31 |
| 🐘Packagist | symfony/symfony | ≥ 6.0.0&&< 6.3.8 | 6.3.8composer require symfony/symfony:^6.3.8 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/twig-bridge, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update symfony/twig-bridge to 4.4.51 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-46734 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-46734 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-46734. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is CVE-2023-46734 in your dependencies?
O3 Security finds CVE-2023-46734 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.