CVE-2026-24739 in Symfony
Summary
by MITRE • 01/28/2026
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.
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Analysis
by VulDB Data Team • 02/12/2026
The vulnerability described in CVE-2026-24739 affects the Symfony Process component across multiple versions of the Symfony framework, specifically before 5.4.51, 6.4.33, 7.3.11, 7.4.5, and 8.0.5. This issue arises from improper handling of special characters, particularly the equals sign, during argument escaping on Windows platforms. The flaw is particularly concerning because it leverages the interaction between PHP running in MSYS2-based environments such as Git Bash and the native Windows executable spawning mechanisms. The root cause lies in how the Symfony Process component treats certain characters as non-special during argument escaping, leading to incorrect behavior when these arguments are processed through MSYS2's argument conversion layer. This misconfiguration creates a scenario where the intended command arguments become corrupted or truncated, potentially leading to severe operational consequences. The vulnerability is classified under CWE-170, which deals with improper handling of a control character, and aligns with ATT&CK technique T1059.003 for executing commands through scripting languages, particularly when those commands are subject to environment-specific argument processing.
The technical flaw manifests when PHP applications utilizing Symfony Process spawn native Windows executables from within MSYS2 environments like Git Bash. During this process, MSYS2's argument conversion mechanism attempts to translate Unix-style paths and arguments into Windows-compatible formats, but fails to properly account for unquoted arguments containing special characters such as the equals sign. This results in argument corruption where the original intent of the command is altered, causing the spawned process to operate on unintended file paths. The impact is particularly severe when dealing with file management operations such as rmdir or del commands, where a path argument containing an equals sign could be misinterpreted, leading to unintended directory deletions or file operations on incorrect targets. This vulnerability represents a classic case of environment-specific argument handling that bypasses standard security controls, creating a path traversal or command injection-like scenario in specific execution contexts.
The operational impact of this vulnerability extends beyond simple command execution errors to potentially enable unauthorized file system modifications or data destruction. When applications or tooling such as Composer scripts utilize Symfony Process to execute system commands with user-provided or configurable paths, the risk becomes significantly elevated. The vulnerability is particularly dangerous in scenarios involving untrusted input sources such as repository paths, extracted archive contents, temporary directories, or user-controlled configuration parameters. Attackers could exploit this weakness by crafting input containing equals signs in file paths, causing the system to execute commands against unintended targets. This could result in data loss, system compromise, or denial of service conditions. The vulnerability also impacts automated tooling and deployment processes that rely on Symfony Process for executing system commands, potentially allowing attackers to manipulate the execution environment in ways that could compromise entire systems or data integrity.
Mitigation strategies for CVE-2026-24739 focus on both environment configuration and code-level protections. The primary recommended approach involves upgrading to patched versions of Symfony 5.4.51, 6.4.33, 7.3.11, 7.4.5, and 8.0.5 where the argument escaping logic has been corrected to properly handle special characters. Alternative workarounds include avoiding execution of PHP applications or tooling from MSYS2-based shells on Windows systems, instead preferring native Windows command environments such as cmd.exe or PowerShell for operations that require spawning native executables. Developers should also avoid passing paths containing equals signs and other MSYS2-sensitive characters to Symfony Process when operating under Git Bash or similar MSYS2 environments. Additional protections can be implemented by configuring MSYS2 to disable or restrict argument conversion through environment variables like MSYS2_ARG_CONV_EXCL, though this may impact compatibility with other tools that depend on MSYS2's argument conversion behavior. Organizations should also implement input validation and sanitization practices to prevent potentially malicious paths containing special characters from reaching the Symfony Process component, particularly in applications handling user-provided data or configuration inputs.