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Actively exploitedKnown ransomware use

CVE-2024-4577 PHP-CGI OS Command Injection Vulnerability

PHP, specifically Windows-based PHP used in CGI mode, contains an OS command injection vulnerability that allows for arbitrary code execution. This vulnerability is a patch bypass for CVE-2012-1823.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 12 Jun 2024.
  • CISA lists it as known to be used in ransomware campaigns.
  • Rated Critical severity (CVSS 9.8, scored by Vendor).
  • It has been in the catalogue for 877 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

In PHP versions 8.1.* before 8.1.29, 8.2.* before 8.2.20, 8.3.* before 8.3.8, when using Apache and PHP-CGI on Windows, if the system is set up to use certain code pages, Windows may use "Best-Fit" behavior to replace characters in command line given to Win32 API functions. PHP CGI module may misinterpret those characters as PHP options, which may allow a malicious user to pass options to PHP binary being run, and thus reveal the source code of scripts, run arbitrary PHP code on the server, etc.

Affected Versions

ProductVersions
PHP Group PHP8.1.* to before 8.1.29
8.2.* to before 8.2.20
8.3.* to before 8.3.8

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for PHP Group PHP. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated critical, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 3 Jul 2024 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

More Exploited PHP Group Flaws

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CVE-2026-109618PHP Memory Corruption VulnerabilityAdded 26 Oct 2026CVE-2026-109619PHP Stale Internal Request-State VulnerabilityAdded 26 Oct 2026

All 3 exploited PHP Group vulnerabilities

Not Sure If You Are Exposed?

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2024-4577
  3. CVE record: CVE-2024-4577
  4. FIRST EPSS
  5. github.com/php/php-src/security/advisories/GHSA-3qgc-jrrr-25jv
  6. blog.orange.tw/2024/06/cve-2024-4577-yet-another-php-rce.html
  7. devco.re/blog/2024/06/06/security-alert-cve-2024-4577-php-cgi-argument-injection-vulnerability-en/
  8. arstechnica.com/security/2024/06/php-vulnerability-allows-attackers-to-run-malicious-code-on-windows
  9. imperva.com/blog/imperva-protects-against-critical-php-vulnerability-cve-2024-4577/
  10. github.com/11whoami99/CVE-2024-4577
  11. github.com/xcanwin/CVE-2024-4577-PHP-RCE
  12. github.com/rapid7/metasploit-framework/pull/19247