CVE-2021-41773
Path traversal and file disclosure vulnerability 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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-41773- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:P/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
CVE List
Path traversal and file disclosure vulnerability 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.
- Record
CVE-2021-41773- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
EUVDEUVD-2021-28781
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.
- Record
EUVD-2021-28781- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-29h7-gr57-5f8r
A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker...
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 expected document root. If files outside of the document root are not protected by "require all denied" these requests can succeed. Additionally this flaw could leak the source of interpreted files like CGI scripts. This issue is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions.
- Record
GHSA-29h7-gr57-5f8r- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
CISA KEV No score
Apache HTTP Server Path Traversal Vulnerability
Apache HTTP Server contains a path traversal vulnerability that allows an attacker to perform remote code execution if files outside directories configured by Alias-like directives are not under default �require all denied� or if CGI scripts are enabled. The original patch issued under this CVE ID is insufficient, please review remediation information under CVE-2021-42013.
- Record
CVE-2021-41773- Weakness
- CWE-22
- Updated
- 2026-11-02
OSVALPINE-CVE-2021-41773
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.
- Record
ALPINE-CVE-2021-41773- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Show 6 moreShow less
OSVBELL-CVE-2021-41773
CVE-2021-41773 does not affect BellSoft software
- Record
BELL-CVE-2021-41773- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSV
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.
- Record
CVE-2021-41773- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-41773
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.
- Record
DEBIAN-CVE-2021-41773- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVBIT-apache-2021-41773 No score
Path traversal and file disclosure vulnerability 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.
- Record
BIT-apache-2021-41773- Updated
- 2026-11-02
OSVMGASA-2021-0461 No score
Updated apache packages fix security vulnerabilities
The updated packages fix a security vulnerabilities:
While fuzzing the 2.4.49 httpd, a new null pointer dereference was detected during HTTP/2 request processing, allowing an external source to DoS the server. This requires a specially crafted request. The vulnerability was recently introduced in version 2.4.49. No exploit is known to the project (CVE-2021-41524).
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 expected document root. If files outside of the document root are not protected by "require all denied" these requests can succeed. Additionally this flaw could leak the source of interpreted files like CGI scripts. This issue is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions (CVE-2021-41773).
- Record
MGASA-2021-0461- Updated
- 2026-11-02
OSVopenSUSE-SU-2024:11560-1 No score
apache2-2.4.51-1.1 on GA media
These are all security issues fixed in the apache2-2.4.51-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2024:11560-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
apache2Alpine:v3.11 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.12 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.13 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.14 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.15 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.16 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.17 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.18 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.19 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.20 |
before 2.4.50-r0 | 2.4.50-r0 |
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| Package | Affected | Fixed |
|---|---|---|
apache2Alpine:v3.21 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.22 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.23 |
before 2.4.50-r0 | 2.4.50-r0 |
apache2Alpine:v3.24 |
before 2.4.50-r0 | 2.4.50-r0 |
apacheBitnami |
2.4.49 up to 2.4.50 | 2.4.50 |
apache2Debian:12 |
before 2.4.50-1 | 2.4.50-1 |
apache2Debian:13 |
before 2.4.50-1 | 2.4.50-1 |
apache2Debian:14 |
before 2.4.50-1 | 2.4.50-1 |
apacheMageia:8 From an advisory covering 2 CVEs |
before 2.4.50-1.mga8 | 2.4.50-1.mga8 |
apache2openSUSE:Tumbleweed From an advisory covering 2 CVEs |
before 2.4.51-1.1 | 2.4.51-1.1 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| Metasploit | Apache 2.4.49/2.4.50 Traversal RCE | 2021-05-10 |
| PoC in GitHub | TishcaTpx/POC-CVE-2021-41773 | 2021-10-05 |
| PoC in GitHub | Vulnmachines/cve-2021-41773 | 2021-10-05 |
| PoC in GitHub | ZephrFish/CVE-2021-41773-PoC | 2021-10-05 |
| PoC in GitHub | iilegacyyii/PoC-CVE-2021-41773 | 2021-10-05 |
| PoC in GitHub | j4k0m/CVE-2021-41773 | 2021-10-05 |
| PoC in GitHub | knqyf263/CVE-2021-41773 | 2021-10-05 |
| PoC in GitHub | lorddemon/CVE-2021-41773-PoC | 2021-10-05 |
| PoC in GitHub | masahiro331/CVE-2021-41773 | 2021-10-05 |
| PoC in GitHub | numanturle/CVE-2021-41773 | 2021-10-05 |
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History
| Recorded | Changed | Sources |
|---|---|---|
| affected | ||
| exploitation | ||
| exploits, exploits_more | ||
| exploits | ||
| first indexed | CVE List, EUVD, Exploit-DB, GitHub Advisories, CISA KEV, Metasploit, Nuclei, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-41773 is a critical vulnerability (CVSS 9.8) in Apache Http Server, published October 5, 2021. CISA lists it as known to be exploited, since November 3, 2021. EUVD reports exploitation since November 3, 2021. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 100.0%, the 99th percentile. Fixed in apache2 2.4.50-r0.
References
httpd.apache.org/security/vulnerabilities_24.html
lists.apache.org/thread.html/r6abf5f2ba6f1aa8b1030f95367aaf17660c4e4c78cb2338aee18982f%40%3Cusers.httpd.apache.org%3E
openwall.com/lists/oss-security/2021/10/05/2
Show 42 moreShow less
tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ
packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal.html
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC
oracle.com/security-alerts/cpujan2022.html
security.netapp.com/advisory/ntap-20211029-0009
security.gentoo.org/glsa/202208-20
cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-41773
nvd.nist.gov/vuln/detail/CVE-2021-41773
github.com/advisories/GHSA-29h7-gr57-5f8r
security.alpinelinux.org/vuln/CVE-2021-41773
docs.bell-sw.com/security/cves/CVE-2021-41773
security-tracker.debian.org/tracker/CVE-2021-41773
advisories.mageia.org/MGASA-2021-0461.html
bugs.mageia.org/show_bug.cgi?id=29530
downloads.apache.org/httpd/Announcement2.4.html
suse.com/security/cve/CVE-2021-41773
The full exploit list has 150 more links.