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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 3 Jul 2024. Known ransomware use
PHPApplication

CVE-2024-4577

CRITICAL · 9.8 CVSS v3.1 Published 2024-06-09
Fix available
A fix is available. Upgrade to 8.1.29 / 8.2.20 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Ransomware High EPSS Public exploit Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A character interpretation vulnerability in PHP-CGI on Windows allows attackers to inject PHP options via command-line arguments when certain code pages trigger Windows 'Best-Fit' behavior. This occurs specifically when Apache runs PHP-CGI and can expose source code or execute arbitrary PHP code.

MitigationUpdate PHP to version 8.1.29+, 8.2.20+, or 8.3.8+ on affected Windows Apache servers, or disable PHP-CGI if not required.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
PHPApplication
Affected:>= 8.1.0, < 8.1.29>= 8.2.0, < 8.2.20>= 8.3.0, < 8.3.8
FedoraOperating system
Affected:= 39= 40

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check PHP version
    Run 'php -v' in command prompt or PowerShell to retrieve the installed PHP version number
    Affected if Version is 8.1.0 through 8.1.28, 8.2.0 through 8.2.19, or 8.3.0 through 8.3.7
  2. Confirm operating system is Windows
    Verify the server or workstation is running Microsoft Windows. This vulnerability only applies to Windows environments
    Affected if System is running any Windows version (Windows Server, Windows 10, Windows 11, etc.)
  3. Verify PHP-CGI is in use
    Check if the web server configuration uses PHP-CGI mode (php-cgi.exe) rather than mod_php or PHP-FPM. Inspect web server configuration files or check if php-cgi.exe process is running
    Affected if PHP-CGI is enabled and accessible via web requests; the vulnerability requires PHP-CGI to be exposed

User is affected if running vulnerable PHP versions (8.1.x below 8.1.29, 8.2.x below 8.2.20, or 8.3.x below 8.3.8) on Windows with PHP-CGI mode enabled and accessible

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 8.1.29 / 8.2.20 / 8.3.8 or later
Fixed in 8.1.298.2.208.3.8
Vendor patch github.com →
Interim mitigation

Update PHP to version 8.1.29+, 8.2.20+, or 8.3.8+ on affected Windows Apache servers, or disable PHP-CGI if not required.

Recommended fix High confidence

PHP 8.1.29+ (8.1 branch), PHP 8.2.20+ (8.2 branch), or PHP 8.3.8+ (8.3 branch)

  1. Identify the current PHP version by running 'php -v' or 'php-cgi -v'
  2. For systems using package managers: Update the package cache (e.g., 'apt update' for Debian/Ubuntu, 'yum check-update' for RHEL/CentOS, or 'dnf check-update' for Fedora)
  3. Upgrade PHP to version 8.1.29 or higher for the 8.1 branch, 8.2.20 or higher for the 8.2 branch, or 8.3.8 or higher for the 8.3 branch
  4. On Fedora systems, run 'dnf update php' or 'dnf update php-cgi' to apply the patched packages
  5. After upgrading, verify the new PHP version with 'php -v' to confirm the fix is applied
  6. Restart Apache web server with 'systemctl restart httpd' or 'apache2ctl restart' to ensure the new PHP-CGI is loaded
  7. Test that PHP scripts execute normally after the upgrade
Caveat Minor: Ensure custom PHP configurations and extensions are compatible with the new minor version; test critical web applications after upgrade

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in PHP Exploited in the wild — priority engagement
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,280
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-4577 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data