| Package | Affected versions | Patched versions |
|---|---|---|
| symfony/symfony | ≥ 6.4.24, < 6.4.40≥ 7.2.9, < 7.4.12≥ 8.0.0, < 8.0.12 | 6.4.407.4.128.0.12 |
| symfony/twig-bridge | ≥ 6.4.24, < 6.4.40 | 6.4.40 |
| symfony/web-profiler-bundle | ≥ 7.2.9, < 7.4.12≥ 8.0.0, < 8.0.12 | 7.4.128.0.12 |
| symfony | ≥ 6.4.24, < 6.4.40≥ 7.2.9, < 7.4.12≥ 8.0.0, < 8.0.12 | 6.4.407.4.128.0.12 |
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.
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.
Symfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.
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