KEV Intelligence

Vulnerability report

Active exploitation observed Confirmed confidence In CISA KEV

CVE-2021-41773

Apache HTTP Server Path Traversal

Apache Software Foundation / Apache HTTP Server · Apache HTTP Server 2.4 2.4.49

View live feed Monitor via API
Severity
CVSS 7.5 · High
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
100.0%
First observed
29 Jun 2026
Last observed
15 Aug 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-41773 is an unauthenticated vulnerability affecting Apache Software Foundation Apache HTTP Server. A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker could use a...

Is it exploited?

Yes. KEV Intelligence sensors observed exploitation attempts with confirmed confidence.

Who is affected?

Apache Software Foundation / Apache HTTP Server apache http server 2.4 2.4.49.

What should we do?

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

Overview

A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49

A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker could use a path traversal attack to map URLs to files outside the directories configured by Alias-like directives. If files outside of these directories are not protected by the usual default configuration "require all denied", these requests can succeed. If CGI scripts are also enabled for these aliased pathes, this could allow for remote code execution.

This issue is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions. The fix in Apache HTTP Server 2.4.50 was found to be incomplete, see CVE-2021-42013.

Vendor Product Affected Status
Apache Software Foundation Apache HTTP Server Apache HTTP Server 2.4 2.4.49 Affected
View vendor advisory (opens in new tab)
Published
05 Oct 2021
Exploitation Reported
03 Nov 2021
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

metasploit ransomware cisa apache malware nuclei_scanner

CVE References

Exploitation evidence

Why KEV Intelligence 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 03 Nov 2021

Independent exploitation attestation added to the KEV Intelligence record.

Active exploitation observed

KEV Intelligence sensor

First observed 09 Jul 2026

First-party sensor telemetry confirms matching exploitation attempts.

Used in malware

CISA

Recorded 03 Nov 2021

Malware families have been linked to exploitation of this CVE.

Proof of concept available

GitHub

Recorded 05 Oct 2021

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

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

Learn about Pro API access
Source Added
CISA First 2021-11-03 00:00 UTC
KEV Intelligence 2026-07-16 15:07 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Aggregate observations show the scale, recency, and distribution of activity without overstating sparse data.

3,723

Attempts observed

578

Unique attacker IPs

51

Attacker countries

AE · AR · BD · BE · BG · BR · CA · CH · CN · CO · DE · DO · ES · FI · FR · GB · HK · ID · IE · IN · IR · JP · KR · KZ · LU · LV · LY · MW · MY · NG · NL · NP · PA · PE · PK · PL · PT · RS · RU · SA · SC · SE · SG · TH · TR · TW · UA · US · UZ · VN · ZM

33

Sensors observed

Exploitation attempts over the last 49 days

Daily events observed by KEV Intelligence sensors

Updated 15 Aug 2026

0
24
69
70
67
465
103
81
78
89
134
135
228
264
182
206
186
198
211
208
184
250
206
239
192
116
86
75
100
86
66
105
112
94
98
94
84
82
87
99
226
85
85
73
90
96
95
110
4
28 Jun 8 Jul 18 Jul 28 Jul 15 Aug

First observed 29 Jun 2026 · Last observed 15 Aug 2026

Pro adds sensor region and window summaries. Enterprise adds raw IPs, paths, User-Agents, and payloads.

Request telemetry access

Detection

Operational artifacts and observed signals

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

Observed signals

Request targets
20
User-Agents
29

Raw values available in Pro and Enterprise.

Virtual patch status

No KEV Intelligence 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/multi/http/apache_normalize_path_rce.rb 28 Apr 2025
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-41773.yaml 25 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

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

EPSS

100.0%

Weaknesses

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') CWE-22

Potential Proof of Concepts

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

Vanshuk-Bhagat/Apache-HTTP-Server-Vulnerabilities-CVE-2021-41773-and-CVE-2021-42013

github · Created 2025-03-11 07:56:58 UTC · 0 stars

In this project, I documented a detailed penetration testing process targeting Apache HTTP Server vulnerabilities, specifically CVE-2021-41773 and CVE-2021-42013, which involve Path Traversal and Remote Code Execution (RCE).

0xc4t/CVE-2021-41773

github · Created 2024-08-26 09:07:33 UTC · 0 stars

POC & Lab For CVE-2021-41773

belajarqywok/CVE-2021-41773-MSF

github · Created 2023-08-11 12:12:09 UTC · 6 stars

Simple Metasploit-Framework module for conducting website penetration tests (CVE-2021-41773).

OfriOuzan/CVE-2021-41773_CVE-2021-42013_Exploits

github · Created 2023-08-02 09:50:10 UTC · 4 stars

Exploit CVE-2021-41773 and CVE-2021-42013

aqiao-jashell/py-CVE-2021-41773

github · Created 2022-11-01 09:17:03 UTC · 7 stars

python编写的apache路径穿越poc&exp

aqiao-jashell/CVE-2021-41773

github · Created 2022-11-01 05:58:59 UTC · 9 stars

apache路径穿越漏洞poc&exp

Habib0x0/CVE-2021-41773

github · Created 2022-06-07 11:22:08 UTC · 2 stars

CVE-2021-41773 | Apache HTTP Server 2.4.49 is vulnerable to Path Traversal and Remote Code execution attacks

Chocapikk/CVE-2021-41773

github · Created 2022-04-12 13:25:58 UTC · 2 stars

zer0qs/CVE-2021-41773

github · Created 2022-03-30 15:04:27 UTC · 0 stars

thehackersbrain/CVE-2021-41773

github · Created 2022-03-12 21:24:55 UTC · 107 stars

Apache2 2.4.49 - LFI & RCE Exploit - CVE-2021-41773

mauricelambert/CVE-2021-41773

github · Created 2022-03-08 21:55:53 UTC · 1 stars

These Metasploit, Nmap, Python and Ruby scripts detects and exploits CVE-2021-41773 with RCE and local file disclosure.

Soliux/CVE-2021-41773

github · Created 2021-11-11 15:10:08 UTC · 2 stars

On the 11/11/21 the apache 2.4.49-2.4.50 remote command execution POC has been published online and this is a loader so that you can mass exploit servers using this.

pirenga/CVE-2021-41773

github · Created 2021-11-11 13:10:05 UTC · 0 stars

Ce programme permet de détecter une faille RCE sur les serveurs Apache 2.4.49 et Apache 2.4.50

Hydragyrum/CVE-2021-41773-Playground

github · Created 2021-11-04 22:52:44 UTC · 6 stars

Some docker images to play with CVE-2021-41773 and CVE-2021-42013

mr-exo/CVE-2021-41773

github · Created 2021-10-26 17:56:25 UTC · 10 stars

Remote Code Execution exploit for Apache servers. Affected versions: Apache 2.4.49, Apache 2.4.50

zerodaywolf/CVE-2021-41773_42013

github · Created 2021-10-18 12:01:58 UTC · 2 stars

Lab setup for CVE-2021-41773 (Apache httpd 2.4.49) and CVE-2021-42013 (Apache httpd 2.4.50).

lopqto/CVE-2021-41773_Honeypot

github · Created 2021-10-16 15:30:34 UTC · 2 stars

Simple honeypot for CVE-2021-41773 vulnerability

LudovicPatho/CVE-2021-41773

github · Created 2021-10-15 21:38:48 UTC · 3 stars

The first vulnerability with the CVE identifier CVE-2021-41773 is a path traversal flaw that exists in Apache HTTP Server 2.4.49.

inbug-team/CVE-2021-41773_CVE-2021-42013

github · Created 2021-10-09 03:32:18 UTC · 147 stars

CVE-2021-41773 CVE-2021-42013漏洞批量检测工具

superzerosec/CVE-2021-41773

github · Created 2021-10-08 15:40:41 UTC · 3 stars

POC

zeronine9/CVE-2021-41773

github · Created 2021-10-08 07:24:49 UTC · 11 stars

Fast python tool to test apache path traversal CVE-2021-41773 in a List of url

corelight/CVE-2021-41773

github · Created 2021-10-08 06:54:27 UTC · 1 stars

A Zeek package which raises notices for Path Traversal/RCE in Apache HTTP Server 2.4.49 (CVE-2021-41773) and 2.4.50 (CVE-2021-42013)

0xRar/CVE-2021-41773

github · Created 2021-10-08 04:26:31 UTC · 7 stars

Exploit for Apache 2.4.49

shellreaper/CVE-2021-41773

github · Created 2021-10-08 01:13:33 UTC · 1 stars

This is a simple POC for Apache/2.4.49 Path Traversal Vulnerability

noflowpls/CVE-2021-41773

github · Created 2021-10-07 12:30:13 UTC · 6 stars

CVE-2021-41773

orangmuda/CVE-2021-41773

github · Created 2021-10-07 00:14:40 UTC · 3 stars

Apache HTTPd (2.4.49) – Local File Disclosure (LFI)

jheeree/Simple-CVE-2021-41773-checker

github · Created 2021-10-06 23:32:30 UTC · 2 stars

Simple script realizado en bash, para revisión de múltiples hosts para CVE-2021-41773 (Apache)

AssassinUKG/CVE-2021-41773

github · Created 2021-10-06 21:37:18 UTC · 2 stars

Apache 2.4.49

n3k00n3/CVE-2021-41773

github · Created 2021-10-06 19:39:25 UTC · 1 stars

exploit to CVE-2021-41773

BlueTeamSteve/CVE-2021-41773

github · Created 2021-10-06 14:47:23 UTC · 20 stars

Vulnerable docker images for CVE-2021-41773

ranggaggngntt/CVE-2021-41773

github · Created 2021-10-06 14:36:05 UTC · 0 stars

1nhann/CVE-2021-41773

github · Created 2021-10-06 14:17:31 UTC · 10 stars

CVE-2021-41773 的复现

jbovet/CVE-2021-41773

github · Created 2021-10-06 13:39:57 UTC · 4 stars

Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49 (CVE-2021-41773)

blasty/CVE-2021-41773

github · Created 2021-10-06 07:17:05 UTC · 208 stars

CVE-2021-41773 playground

creadpag/CVE-2021-41773-POC

github · Created 2021-10-06 05:34:48 UTC · 8 stars

CVE-2021-41773

habibiefaried/CVE-2021-41773-PoC

github · Created 2021-10-06 03:01:41 UTC · 4 stars

PoC for CVE-2021-41773 with docker to demonstrate

itsecurityco/CVE-2021-41773

github · Created 2021-10-06 02:30:40 UTC · 11 stars

CVE-2021-41773 POC with Docker

Ls4ss/CVE-2021-41773_CVE-2021-42013

github · Created 2021-10-06 02:28:41 UTC · 21 stars

Apache HTTP Server 2.4.49, 2.4.50 - Path Traversal & RCE

lorddemon/CVE-2021-41773-PoC

github · Created 2021-10-05 23:53:48 UTC · 37 stars

TishcaTpx/POC-CVE-2021-41773

github · Created 2021-10-05 20:41:34 UTC · 6 stars

Poc.py

j4k0m/CVE-2021-41773

github · Created 2021-10-05 20:30:01 UTC · 12 stars

Exploitation of CVE-2021-41773 a Directory Traversal in Apache 2.4.49.

iilegacyyii/PoC-CVE-2021-41773

github · Created 2021-10-05 17:30:43 UTC · 47 stars

ZephrFish/CVE-2021-41773-PoC

github · Created 2021-10-05 17:29:49 UTC · 17 stars

knqyf263/CVE-2021-41773

github · Created 2021-10-05 16:45:41 UTC · 10 stars

Path traversal in Apache HTTP Server 2.4.49 (CVE-2021-41773)

numanturle/CVE-2021-41773

github · Created 2021-10-05 16:18:09 UTC · 9 stars

CVE-2021-41773

Apache 2.4.49 - Path Traversal and Remote Code Execution

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. Observed by KEV Intelligence sensors

    Evidence-backed exploitation signal

  2. Indicators of compromise added (998)

    Indicators of compromise recorded

  3. Metasploit module available

    Exploit module available

  4. Nuclei template available

    Scanner coverage available

  5. Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  6. First public exploitation report

    Exploit observed in malware

  7. Public PoC available

    Public proof-of-concept code published

  8. CVE published

    Vulnerability disclosed publicly

  9. 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.

View Pro pricing Read API docs
  • 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-2021-41773

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2021-41773",
  "confidence": "Confirmed",
  "cvss_score": 7.5,
  "epss_score": 0.99992,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 3723, "sensors": 33 }
}

Early warning alerts

Get alerts on high-impact exploitation

Receive curator-selected alerts when exploitation activity warrants attention. Each alert includes the evidence and context needed to decide what requires attention now.

Occasional high-impact alerts. Unsubscribe anytime. See our Privacy Policy.