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High · 7.5 Known exploited · Ransomware Scanner template Public exploit CVE-2021-41773 EUVD-2021-28781GHSA-29h7-gr57-5f8r

Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49

Published Oct 5, 2021 · Updated Oct 21, 2025 · Assigned by apache

Vendor: Apache Software Foundation Product: Apache HTTP Server Package: apache2 Package: apache2 Ecosystem: Alpine Ecosystem: Debian

Description

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.

Affected products

VendorProductAffectedFixed
Apache Software Foundation Apache HTTP Server Apache HTTP Server 2.4 2.4.49 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

Debian

Security tracker ↗
ReleasePackageFixed inAdvisory
Debian 14 apache2 2.4.50-1 —
Debian 13 apache2 2.4.50-1 —
Debian 12 apache2 2.4.50-1 —

openSUSE

Security tracker ↗
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed apache2 2.4.51-1.1 openSUSE-SU-2024:11560-1

Alpine

Security tracker ↗
ReleasePackageFixed inAdvisory
Alpine v3.24 apache2 2.4.50-r0 —
Alpine v3.23 apache2 2.4.50-r0 —
Alpine v3.22 apache2 2.4.50-r0 —
Alpine v3.21 apache2 2.4.50-r0 —
Alpine v3.20 apache2 2.4.50-r0 —
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Alpine v3.19 apache2 2.4.50-r0 —
Alpine v3.18 apache2 2.4.50-r0 —
Alpine v3.17 apache2 2.4.50-r0 —
Alpine v3.16 apache2 2.4.50-r0 —
Alpine v3.15 apache2 2.4.50-r0 —
Alpine v3.14 apache2 2.4.50-r0 —
Alpine v3.13 apache2 2.4.50-r0 —
Alpine v3.12 apache2 2.4.50-r0 —
Alpine v3.11 apache2 2.4.50-r0 —

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2 httpd +7 2.4.51-1.amzn2 ALAS2-2021-1716
Amazon Linux 2 mod_ssl +1 1:2.4.51-1.amzn2 ALAS2-2021-1716

Public exploits

Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.

Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.

Metasploit 2 modules

Exploit-DB 2

GitHub 175 repositories · most starred shown

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

Automated scanner template

A ready-made Nuclei template detects this vulnerability automatically. Vulnerabilities with public scanner templates are typically probed across the internet soon after the template appears — exposed systems should be patched first.

Source: projectdiscovery/nuclei-templates (MIT) — updated daily. Only links are listed.

Advisories 3

References