CVE-2026-24739

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 mishandle unquoted arguments containing these characters.

This can cause the spawned process to receive corrupted/truncated arguments compared to what Symfony intended.

Resolution

Upgrade to a Symfony release that includes the fix from symfony/symfony#63164 (which updates Windows argument escaping to ensure arguments containing = and other MSYS2-sensitive characters are properly quoted/escaped).
The patch for branch 5.4 is available at https://github.com/symfony/symfony/commit/ec154f6f95f8c60f831998ec4d246a857e9d179b

Workarounds / Mitigations

Avoid running PHP/your 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.

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).

CVE-2026-24739 has a CVSS score of 6.3 (Medium). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.4.51, 6.4.33, 7.3.11, 7.4.5, 8.0.5); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-24739? CVE-2026-24739 is a medium-severity security vulnerability in symfony/process (composer), affecting versions < 5.4.51. It is fixed in 5.4.51, 6.4.33, 7.3.11, 7.4.5, 8.0.5.
2. How severe is CVE-2026-24739? CVE-2026-24739 has a CVSS score of 6.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2026-24739?
   • symfony/process (composer) (versions < 5.4.51)
   • symfony/symfony (composer) (versions < 5.4.51)
4. Is there a fix for CVE-2026-24739? Yes. CVE-2026-24739 is fixed in 5.4.51, 6.4.33, 7.3.11, 7.4.5, 8.0.5. Upgrade to this version or later.
5. Is CVE-2026-24739 exploitable, and should I be worried? Whether CVE-2026-24739 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-24739 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-24739?
   • Upgrade symfony/process to 5.4.51 or later
   • Upgrade symfony/process to 6.4.33 or later
   • Upgrade symfony/process to 7.3.11 or later
   • Upgrade symfony/process to 7.4.5 or later
   • Upgrade symfony/process to 8.0.5 or later
   • Upgrade symfony/symfony to 5.4.51 or later
   • Upgrade symfony/symfony to 6.4.33 or later
   • Upgrade symfony/symfony to 7.3.11 or later
   • Upgrade symfony/symfony to 7.4.5 or later
   • Upgrade symfony/symfony to 8.0.5 or later