CVE-2021-42013

Apache HTTP Server Path Traversal

9.8 CRITICALActively exploited (CISA KEV)Used in ransomwarePublic exploitEPSS 100.0%

Published7 Oct 2021
Added to CISA KEV3 Nov 2021
Remediation due17 Nov 2021

Description

It was found that the fix for CVE-2021-41773 in Apache HTTP Server 2.4.50 was insufficient. 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 only affects Apache 2.4.49 and Apache 2.4.50 and not earlier versions.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Affected products

Apache HTTP Server2.4.49 · 2.4.50

Netapp Cloud Backupall versions

Oracle Instantis Enterprisetrack17.1 · 17.2 · 17.3

Oracle Jd Edwards Enterpriseone Tools< 9.2.6.0

Oracle Secure Backup< 18.1.0.1.0

Fedoraproject Fedora34 · 35

Remediation

Fixed in

Oracle Jd Edwards Enterpriseone Tools≥ 9.2.6.0

Oracle Secure Backup≥ 18.1.0.1.0

Patch & vendor advisories

References

http://jvn.jp/en/jp/JVN51106450/index.htmlThird Party Advisory
http://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.htmlExploitThird Party AdvisoryVDB Entry
http://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlExploitThird Party AdvisoryVDB Entry
http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.htmlExploitThird Party AdvisoryVDB Entry
http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlExploitThird Party AdvisoryVDB Entry
http://packetstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.htmlThird Party AdvisoryVDB Entry
http://packetstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.htmlExploitThird Party AdvisoryVDB Entry
https://httpd.apache.org/security/vulnerabilities_24.htmlRelease NotesVendor Advisory
https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3EMailing ListPatch
https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3EMailing List

and 21 more references

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2021-42013 being actively exploited?

Yes. CVE-2021-42013 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 3 Nov 2021. It has been used in ransomware campaigns.

How severe is CVE-2021-42013?

CVE-2021-42013 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 100.0% probability of exploitation.

Which products are affected by CVE-2021-42013?

Affected products include Apache HTTP Server, Netapp Cloud Backup, Oracle Instantis Enterprisetrack, Oracle Jd Edwards Enterpriseone Tools, Oracle Secure Backup, and 1 more.

How do I fix CVE-2021-42013?

Upgrade affected software to a fixed version, for example Oracle Jd Edwards Enterpriseone Tools 9.2.6.0, Oracle Secure Backup 18.1.0.1.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2021-42013 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.