CVE-2021-41773
Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49
At a glance
- Severity
- HIGH 7.5
- Exploitation
- Known exploited (CISA KEV) · added 2021-11-03
Exploited per ENISA since 2021-11-03 - EPSS
- EPSS 99.99 % · percentile 100 (2026-10-27)
- State
- PUBLISHED
- Published
- Updated
- Assigner
- apache
- NVD status
- Analyzed
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.
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | CISA-ADP |
| CVSS 3.1 | CRITICAL 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | NVD · nvd@nist.gov (Primary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) |
| CVSS 2.0 | MEDIUM 4.3 | AV:N/AC:M/Au:N/C:P/I:N/A:N | NVD · nvd@nist.gov (Primary) |
Weaknesses (CWE)
European references
- ENISA EUVD · EUVD-2021-28781
- GCVE · GCVE-0-2021-41773
CERT-FR advisories
- CERTFR-2024-AVI-0575 — Multiples vulnérabilités dans les produits Juniper Networks · cert.ssi.gouv.fr
- CERTFR-2021-AVI-759 — Multiples vulnérabilités dans Apache HTTP Server · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:apache:http_server:2.4.49:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*cpe:2.3:a:oracle:instantis_enterprisetrack:17.1:*:*:*:*:*:*:*cpe:2.3:a:oracle:instantis_enterprisetrack:17.2:*:*:*:*:*:*:*cpe:2.3:a:oracle:instantis_enterprisetrack:17.3:*:*:*:*:*:*:*cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| Apache Software Foundation · Apache HTTP Server | affected Apache HTTP Server 2.4 2.4.49 |
References
- https://httpd.apache.org/security/vulnerabilities_24.html
- https://lists.apache.org/thread.html/r6abf5f2ba6f1aa8b1030f95367aaf17660c4e4c78cb2338aee18982f%40%3Cusers.httpd.apache.org%3E
- https://lists.apache.org/thread.html/r98d704ed4377ed889d40479db79ed1ee2f43b2ebdd79ce84b042df45%40%3Cannounce.apache.org%3E
- http://www.openwall.com/lists/oss-security/2021/10/05/2
- http://www.openwall.com/lists/oss-security/2021/10/07/1
- https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3E
- https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3E
- http://www.openwall.com/lists/oss-security/2021/10/07/6
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ
- http://www.openwall.com/lists/oss-security/2021/10/08/1
- https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3E
- http://www.openwall.com/lists/oss-security/2021/10/08/2
- http://www.openwall.com/lists/oss-security/2021/10/08/3
- http://www.openwall.com/lists/oss-security/2021/10/08/4
- http://www.openwall.com/lists/oss-security/2021/10/08/6
- http://www.openwall.com/lists/oss-security/2021/10/08/5
- http://www.openwall.com/lists/oss-security/2021/10/09/1
- http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal.html
- http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal-Remote-Code-Execution.html
- http://www.openwall.com/lists/oss-security/2021/10/11/4
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/
- http://www.openwall.com/lists/oss-security/2021/10/15/3
- http://www.openwall.com/lists/oss-security/2021/10/16/1
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://security.netapp.com/advisory/ntap-20211029-0009/
- http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html
- http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html
- https://security.gentoo.org/glsa/202208-20
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-41773
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| CISA Known Exploited Vulnerabilities | CC0 1.0 |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |