CVE-2024-24821 is a high-severity (CVSS 8.8) CWE-829 vulnerability in composer/composer. A fix is available for composer/composer — see the affected versions and patch details below.
Code execution and possible privilege escalation via compromised InstalledVersions.php or installed.php in Composer
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- 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-2024-24821.
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.
How urgent is this, really
CVE-2024-24821 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
composer/composer🐘composer/composerReal-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
Composer is a dependency Manager for the PHP language. In affected versions several files within the local working directory are included during the invocation of Composer and in the context of the executing user. As such, under certain conditions arbitrary code execution may lead to local privilege escalation, provide lateral user movement or malicious code execution when Composer is invoked within a directory with tampered files. All Composer CLI commands are affected, including composer.phar's self-update. The following scenarios are of high risk: Composer being run with sudo, Pipelines which may execute Composer on untrusted projects, Shared environments with developers who run Composer individually on the same project. This vulnerability has been addressed in versions 2.7.0 and 2.2.23. It is advised that the patched versions are applied at the earliest convenience. Where not possible, the following should be addressed: Remove all sudo composer privileges for all users to mitigate root privilege escalation, and avoid running Composer within an untrusted directory, or if needed, verify that the contents of vendor/composer/InstalledVersions.php and vendor/composer/installed.php do not include untrusted code. A reset can also be done on these files by the following:```sh
rm vendor/composer/installed.php vendor/composer/InstalledVersions.php
composer install --no-scripts --no-plugins
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | composer/composer | ≥ 2.0.0-alpha1&&< 2.2.23 | 2.2.23composer require composer/composer:^2.2.23 |
| 🐘Packagist | composer/composer | ≥ 2.3.0-rc1&&< 2.7.0 | 2.7.0composer require composer/composer:^2.7.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for composer/composer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update composer/composer to 2.2.23 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-24821 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-24821 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-24821. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is CVE-2024-24821 in your dependencies?
O3 Security finds CVE-2024-24821 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.