CVE-2026-24739
MEDIUMSymfony has incorrect argument escaping under MSYS2/Git Bash on Windows that can lead to destructive file operations
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.
Blast Radius
symfony/process🐘symfony/process🐘symfony/process🐘symfony/process🐘symfony/process🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony+2 moreReal-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. Prior to versions 5.4.51, 6.4.33, 7.3.11, 7.4.5, and 8.0.5, the Symfony Process component did not correctly treat some characters (notably =) as “special” when escaping arguments on Windows. When PHP is executed from an MSYS2-based environment (e.g. Git Bash) and Symfony Process spawns native Windows executables, MSYS2’s argument/path conversion can mis-handle unquoted arguments containing these characters. This can cause the spawned process to receive corrupted/truncated arguments compared to what Symfony intended. If an application (or tooling such as Composer scripts) uses Symfony Process to invoke file-management commands (e.g. rmdir, del, etc.) with a path argument containing =, the MSYS2 conversion layer may alter the argument at runtime. In affected setups this can result in operations being performed on an unintended path, up to and including deletion of the contents of a broader directory or drive. The issue is particularly relevant when untrusted input can influence process arguments (directly or indirectly, e.g. via repository paths, extracted archive paths, temporary directories, or user-controlled configuration). Versions 5.4.51, 6.4.33, 7.3.11, 7.4.5, and 8.0.5 contains a patch for the issue. Some workarounds are available. Avoid running PHP/one's own tooling from MSYS2-based shells on Windows; prefer cmd.exe or PowerShell for workflows that spawn native executables. Avoid passing paths containing = (and similar MSYS2-sensitive characters) to Symfony Process when operating under Git Bash/MSYS2. Where applicable, configure MSYS2 to disable or restrict argument conversion (e.g. via MSYS2_ARG_CONV_EXCL), understanding this may affect other tooling behavior.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/process | all versions | 5.4.51 |
| 🐘Packagist | symfony/process | ≥ 6.4&&< 6.4.33 | 6.4.33 |
| 🐘Packagist | symfony/process | ≥ 7.3&&< 7.3.11 | 7.3.11 |
| 🐘Packagist | symfony/process | ≥ 7.4&&< 7.4.5 | 7.4.5 |
| 🐘Packagist | symfony/process | ≥ 8.0&&< 8.0.5 | 8.0.5 |
| 🐘Packagist | symfony/symfony | all versions | 5.4.51 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/process. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update symfony/process to 5.4.51 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-24739 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 pinpoints whether CVE-2026-24739 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-24739. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-24739 in your dependencies?
O3 detects CVE-2026-24739 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.