Vulnerability report

Active exploitation observed Confirmed confidence In CISA KEV

CVE-2024-4577

Argument Injection in PHP-CGI

PHP Group / PHP · affected before 8.1.29

Watch CVE-2024-4577 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
100.0%
First observed
21 Jul 2026
Last observed
09 Oct 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2024-4577 is an unauthenticated Argument Injection in PHP-CGI. 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...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

PHP Group / PHP affected before 8.1.29.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

Argument Injection in PHP-CGI

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.

php_group Affected
php
Before 8.1.29 Before 8.2.20 Before 8.3.8
PHP Group Affected
PHP
Before 8.1.29 Before 8.2.20 Before 8.3.8
Published
09 Jun 2024
Exploitation Reported
12 Jun 2024
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

windows nuclei_scanner ransomware malware nessus_scanner metasploit apache php cisa

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 12 Jun 2024

A trusted third party reported exploitation.

Active exploitation observed

Previdian sensor

First observed 21 Jul 2026

Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.

Used in malware

CISA

Recorded 12 Jun 2024

Malware families have been linked to exploitation of this CVE.

Proof of concept available

Recorded 28 Apr 2025

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CISA First 2024-06-12 00:00 UTC
The Shadowserver 2026-05-31 00:00 UTC
Previdian Sensors 2026-08-20 18:39 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.

35,226

Attempts observed

1,551

Unique attacker IPs

76

Attacker countries

AE · AF · AM · AR · AT · AU · BD · BE · BG · BR · CA · CH · CM · CN · CO · DE · DK · DO · DZ · EE · ES · ET · FI · FR · GB · GE · GT · HK · HU · ID · IN · IQ · IR · IS · IT · JP · KR · KZ · LK · LT · LV · LY · MA · MD · MW · MX · MY · MZ · NL · NP · NZ · PA · PE · PH · PK · PL · PT · PY · RS · RU · SA · SC · SE · SG · SI · SO · TH · TR · TW · UA · US · UZ · VN · YE · ZA · ZM

76

Sensors observed

CVE-2024-4577 exploitation attempts over the last 82 days

Daily events observed by Previdian sensors

Updated 09 Oct 2026

0
28
154
110
96
102
163
231
105
80
140
217
167
250
190
196
264
222
489
239
271
179
253
334
240
320
236
265
253
254
332
309
265
355
320
845
449
401
253
339
360
393
403
436
511
454
376
358
454
389
352
379
465
430
538
422
487
482
341
396
511
568
581
543
676
603
565
622
937
856
983
729
843
929
922
1,034
914
1,245
871
845
978
129
20 Jul 6 Aug 23 Aug 9 Sep 9 Oct

First observed 21 Jul 2026 · Last observed 09 Oct 2026

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Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
33
104
2

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/http/php_cgi_arg_injection_rce_cve_2024_4577.rb 28 Apr 2025
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2024/CVE-2024-4577.yaml 25 Apr 2025
Nessus https://www.tenable.com/plugins/nessus/214953 04 Feb 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

Potential damage if exploited. Separate from whether attackers are using it.

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

EPSS

100.0%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') CWE-78

Recent mention · RecordedFuture

August 2026 CVE Landscape

In August 2026, Insikt Group® identified 73 high-impact vulnerabilities that should be prioritized for remediation, 43 of which had a Very Critical Recorded Future Risk Score. This represents a 14% decrease from last month.

Read full advisory

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

PHP CGI - Argument Injection

nuclei · Created Unknown

php_cgi_arg_injection_rce_cve_2024_4577

metasploit · Created Unknown

Metasploit module for CVE-2024-4577

Timeline

From disclosure to observed exploitation

  1. 18:44 UTC

    Indicators of compromise added (1551)

    Indicators of compromise recorded

  2. 18:44 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

  3. 00:00 UTC

    KEV confirmed by The Shadowserver

    Exploitation attested by an external source

  4. 15:02 UTC

    Metasploit module available

    Exploit module available

  5. 15:02 UTC

    Public PoC available

    Public proof-of-concept code published

  6. 00:00 UTC

    Nuclei template available

    Scanner coverage available

  7. 20:07 UTC

    Nessus plugin available

    Scanner coverage available

  8. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  9. 00:00 UTC

    First public exploitation report

    Exploit observed in malware

  10. 19:42 UTC

    CVE published

    Vulnerability disclosed publicly

  11. 22:21 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2024-4577

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2024-4577",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.99987,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 35226, "sensors": 76 }
}