How severe is CVE-2026-45072?

No CVSS score has been assigned to CVE-2026-45072 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-45072?

CVE-2026-45072 affects the following packages: symfony/symfony (Packagist), symfony/symfony (Packagist), symfony/symfony (Packagist), symfony/twig-bridge (Packagist), symfony/web-profiler-bundle (Packagist), symfony/web-profiler-bundle (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-45072?

Update symfony/symfony to 6.4.40 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-45072 is resolved across your whole dependency graph.

How do I detect CVE-2026-45072 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/symfony, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-45072 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-45072 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-45072 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-45072?

CVE-2026-45072 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 21th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-45072?

CVE-2026-45072 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-45072 published, and has it been updated?

CVE-2026-45072 was published on July 14, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-45072 — symfony

Fix: symfony/symfony@863aa81

CVE-2026-45072 is a Cross-site Scripting (XSS) vulnerability in symfony/symfony. A fix is available for symfony/symfony — see the affected versions and patch details below.

Symfony: Stored XSS in WebProfiler CodeExtension::fileExcerpt() — Unescaped Non-PHP File Rendering

Also known asGHSA-hmr5-2xcr-v8pp

Published

Jul 14, 2026

Updated

Aug 12, 2026

Affected

6 pkgs

Patched

6 / 6

Exploits

None indexed

Exploitation data as of Oct 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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-2026-45072.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs21th percentile — riskier than 21% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

6 pkgs affected

🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/twig-bridge🐘symfony/web-profiler-bundle🐘symfony/web-profiler-bundle

Real-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's profiler, a development only debug UI, renders source-code excerpts on several pages using Twig's custom file_excerpt filter. This filter renders PHP files via highlight_string() (which escapes HTML), but renders non-PHP files by splitting on \n and interpolating each line directly into <code>{$line}</code> with no escaping.

An attacker who can write arbitrary bytes into any file under the project root (including e.g. var/log/dev.log), achieves stored XSS against any developer who later opens that file in the profiler.

Resolution

The file_excerpt filter now properly escapes each line of non-PHP files using htmlspecialchars() before concatenating them.

The patch for this issue is available here for branch 6.4.

Credits

Symfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.

Affected Packages

6 total 6 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`symfony/symfony`	≥ 6.4.24&&< 6.4.40	6.4.40`composer require symfony/symfony:^6.4.40`
🐘Packagist	`symfony/symfony`	≥ 7.2.9&&< 7.4.12	7.4.12`composer require symfony/symfony:^7.4.12`
🐘Packagist	`symfony/symfony`	≥ 8.0.0&&< 8.0.12	8.0.12`composer require symfony/symfony:^8.0.12`
🐘Packagist	`symfony/twig-bridge`	≥ 6.4.24&&< 6.4.40	6.4.40`composer require symfony/twig-bridge:^6.4.40`
🐘Packagist	`symfony/web-profiler-bundle`	≥ 7.2.9&&< 7.4.12	7.4.12`composer require symfony/web-profiler-bundle:^7.4.12`
🐘Packagist	`symfony/web-profiler-bundle`	≥ 8.0.0&&< 8.0.12	8.0.12`composer require symfony/web-profiler-bundle:^8.0.12`

Affected Products

1 product · 3 configurations

Application

symfonysensiolabs

≥ 8.0.0 && < 8.0.12

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/symfony, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update symfony/symfony to 6.4.40 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-45072 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

### Description Symfony's profiler, a development only debug UI, renders source-code excerpts on several pages using Twig's custom `file_excerpt` filter. This filter renders PHP files via `highlight_string()` (which escapes HTML), but renders **non-PHP files** by splitting on `\n` and interpolating each line directly into `<code>{$line}</code>` with no escaping. An attacker who can write arbitrary bytes into any file under the project root (including e.g. `var/log/dev.log`), achieves **stored XSS** against any developer who later opens that file in the profiler. ### Resolution The `file_e