Security readout for executives and security teams
CVE-2021-42013 is a critical Apache HTTP Server flaw where the previous fix for CVE-2021-41773 was incomplete. A vulnerable server may let an unauthenticated attacker reach files outside intended web directories, and remote code execution is possible when CGI scripts are enabled and exposed. Exposure is most likely on internet-facing Apache HTTP Server 2.4.49 or 2.4.50 systems, especially where Alias-like directives and CGI are enabled or directory access controls are weaker than default. Treat this as urgent for any exposed Apache HTTP Server 2.4.49 or 2.4.50 instance. KEV status and potential remote code execution justify immediate inventory, remediation, and log review. Mitigation focus: Identify and remove Apache HTTP Server 2.4.49 and 2.4.50 from production exposure.; Upgrade or patch according to current Apache HTTP Server vendor guidance.; Disable CGI where it is not required..
Michael Williams reviewed this cited source version on .
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-22: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-42013 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://httpd.apache.org/security/vulnerabilities_24.htmlCVE reference · x_refsource_MISC
- [announce] 20211007 CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773)CVE reference · mailing-list, x_refsource_MLIST
- [httpd-users] 20211007 [users@httpd] CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773)CVE reference · mailing-list, x_refsource_MLIST
- 20211007 Apache HTTP Server Vulnerabilties: October 2021CVE reference · vendor-advisory, x_refsource_CISCO
- [httpd-cvs] 20211008 [httpd-site] branch main updated: * Align with CVE-2021-42013 based on the latest findingsCVE reference · mailing-list, x_refsource_MLIST
- FEDORA-2021-2a10bc68a4CVE reference · vendor-advisory, x_refsource_FEDORA
- FEDORA-2021-aaf90ef84aCVE reference · vendor-advisory, x_refsource_FEDORA
- https://www.oracle.com/security-alerts/cpujan2022.htmlCVE reference · x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20211029-0009/CVE reference · x_refsource_CONFIRM
- https://www.oracle.com/security-alerts/cpuapr2022.htmlCVE reference · x_refsource_MISC
- https://www.povilaika.com/apache-2-4-50-exploit/CVE reference · x_refsource_MISC
- GLSA-202208-20CVE reference · vendor-advisory, x_refsource_GENTOO
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42013CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.