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CVE-2021-42013

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 t…

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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 9.8 (CRITICAL) KEV: KNOWN CATALOG

Attention and evidence

HYPE SCORE
0.0/10
REALITY · THREAT PRIORITY
9.0/10
General review priority; not probability

Evidence confidence: Exploitation recorded

Why this priority?
  • Recorded exploitation baseline: +7.00
  • Technical severity: CVSS 9.8: +1.47
  • Fresh EPSS: 99.96%: +0.50

General review priority, not probability, victim count or asset-specific risk. A range covers missing CVSS/EPSS inputs within the current evidence state.

Sources: 8 documents and public datasets.

Hype components

Headline sample (25%)
0/100
Press, 30 days (60%)
0/100
Grounded branding (15%)
0/100
HYPE TOTAL0/100

Sources and documents

Rescana
Press · 06 Oct 2024, 07:00 · Exploiting CVE-2021-41773: Critical Path Traversal Vulnerability in Apache HTTP Server 2.4.49 - Rescana
www.trendmicro.com
Press · 21 Dec 2021, 08:00 · How to detect Apache HTTP Server Exploitation - www.trendmicro.com
Qualys
Press · 27 Oct 2021, 07:00 · Apache HTTP Server Path Traversal & Remote Code Execution (CVE-2021-41773 & CVE-2021-42013) - Qualys
Arctic Wolf
Press · 08 Oct 2021, 07:00 · CVE-2021-41773 & CVE-2021-42013 - Arctic Wolf
wiz.io
Press · 08 Oct 2021, 07:00 · Protecting cloud environments from the new critical Apache HTTP Server vulnerability - wiz.io
See all 8 source documents
Cisco Talos Blog
Press · 07 Oct 2021, 07:00 · Threat Advisory: Apache HTTP Server zero-day vulnerability opens door for attackers - Cisco Talos Blog
BleepingComputer
Press · 07 Oct 2021, 07:00 · Apache emergency update fixes incomplete patch for exploited bug - BleepingComputer
Rapid7
Press · 06 Oct 2021, 07:00 · Apache HTTP Server CVE-2021-41773 Exploited in the Wild - Rapid7

Score evolution

● Hype   ● Reality

Earlier evidence-support scores are retained in history; this chart shows only the current priority definition.

First record: hype 0.0 · reality 9.0 (2026-11-02 15:12). The curve appears once the score changes.

Public exploit evidence

7

Public exploit entries / repo candidates

See 7 repos with metrics
RepositoryStarsForksLanguageUpdated
CLincat/vulcat13317Python14 Apr 2026, 14:44
blackn0te/Apache-HTTP-Server-2.4.49-2.4.50-Path-Traversal-Remote-Code-Execution130Python22 Aug 2025, 10:05
asaotomo/CVE-2021-42013-Apache-RCE-Poc-Exp102Python24 Dec 2021, 07:38
TheLastVvV/CVE-2021-42013_Reverse-Shell72Shell24 Oct 2021, 13:26
TheLastVvV/CVE-2021-4201320Shell23 Oct 2021, 22:00
lmcewen9/cve-2021-4201300Python07 Oct 2026, 13:58
Makavellik/POC-CVE-2021-42013-EXPLOIT00Python06 Sep 2025, 00:41
Public exploit evidence
Evidence context and dated references

Reality is general threat/review priority, combining observed exploitation, CVSS severity and fresh EPSS. Evidence confidence is separate. This is not calibrated risk, a victim count or an asset-specific assessment. A range reflects missing numeric inputs.

Evidence in context

Confidence in exploitation evidence
Exploitation recorded
Priority basis
Recorded exploitation; CVSS 9.8; EPSS 100.0%
Attention, last 30 days
0 distinct story titles; 0 press documents; 0 publisher domains.
Technical potential
network access, no prior privileges, no user interaction.
Observed activity
Exploitation recorded in CISA KEV.
Known scale
Not quantified.
Evidence confidence basis
Trusted exploitation confirmation

Score evaluated: 2026-11-05 13:58:31.036516+00:00 · EPSS snapshot: 2026-11-05T12:03:04Z

Source event timeline
First press mention
06 Oct 2021, 07:00
Published
07 Oct 2021, 15:50
Added to the CISA KEV catalog
03 Nov 2021, 00:00
Latest press mention
06 Oct 2024, 07:00
Score calculated
05 Nov 2026, 13:58
PoCs on GitHub
7 repositories