CVE Intel / CVE-2021-42013

CVE-2021-42013

Cloud Backup · apache, fedoraproject, netapp, oracle

⚠

Actively exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalogue: exploitation confirmed in the wild. Patch on priority.

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This CVE is being exploited. Apply the vendor fix, or take the service off the internet until you can, then check your logs for attempts.

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CISA KEVexploited on our sensorsCritical CVSS 9.8network detectablepublic exploit: ExploitDB, Metasploit

What it is

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.

Live exploitation on the huntback network (30 days)

1,341

attempts captured

415

distinct source IPs

2026-11-12

last seen

Detection

huntback carries a network signature for this CVE. Exploitation attempts are detected on the decoy fleet in real time.

ExploitDBExploit code published (ExploitDB)

MetasploitExploit code published (Metasploit)

NucleiNuclei detection template available

Evidence

Confirmed exploited. Our decoys saw 207 exploitation attempts in the last 14 days; CISA added it to KEV 1835 days ago.

2026-11-12Observed · huntback decoys
Last attempt. 1,341 attempts on our decoys, 207 in the last 14 days

2026-09-14Observed · huntback decoys
First exploitation attempt on our decoys

2021-11-03Reported · CISA KEV
Added to CISA Known Exploited Vulnerabilities

2021-10-07Context · CVE record
Published

undatedWeaponised · ExploitDB
Exploit code published (ExploitDB)

undatedWeaponised · Metasploit
Exploit code published (Metasploit)

undatedWeaponised · Nuclei
Nuclei detection template available

Observed: our own decoys saw it. Reported: CISA, the vendor or another named source says so. Weaponised: public exploit code or a scanner template exists. Methodology

Questions

Is CVE-2021-42013 being exploited in the wild?

Yes. The huntback decoy network captured 1,341 exploitation attempts from 415 distinct source IPs; the most recent was on 2026-11-12. It is also in the CISA KEV catalogue.

Can CVE-2021-42013 be detected on the network?

Yes. huntback carries a network signature for CVE-2021-42013, so attempts against a decoy are tagged in real time.

How huntback helps

Deploy a decoy that emulates Cloud Backup and you will see every attempt at this CVE the moment it lands, with the full payload, the attacker's infrastructure, and any stage-2 loader. Then huntback can scan the attacker back.

CVSS9.8 Critical

EPSS1.00 (99% pct)

In CISA KEVyes

Published2021-10-07

Updated2026-06-17

Network detectableyes, signatured

Public exploitExploitDB, Metasploit

NVD record → Browse all CVEs → Live malware and C2 finds → Novel-attack discovery → Deploy a decoy →

API

This record, with its evidence timeline, as JSON:

curl -H "X-API-Key: $HUNTBACK_KEY" https://app.huntback.io/api/v1/evidence/CVE-2021-42013

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