CVE-2021-41773

CRITICALNVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score elevated to 9.8 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 9.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 5 sources updated this weekExploited in the wild
9.8
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • 1 internet-exposed host is running an affected version right now
  • Actively exploited in the wild (CISA-KEV)
  • Linked to ransomware campaigns
CISA-KEV: ExploitedEPSS: 100%CVSS: 9.8Exploit: NoneExposed: 1

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

Live · internet exposure

1 internet-exposed host is running an affected version of CVE-2021-41773 right now.

across 1 countries (Swaziland)top: http_server🔒 ransomware-linked
See the live KEV-Exposure radar →Found passively from public internet-scan data — aggregate, host-redacted.

EchelonGraph is the only CVE feed that fuses live vulnerability intelligence with its own live internet-exposure radar — so you see not just that a CVE is exploited, but how much of the internet is exposed to it right now.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
99(Act)
EG Risk 99/100SSVC: Act

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation100% × 40%
Automatability100% × 15%
Action: Fix now — active exploitation, automatable, high impact.
EPSS
100.0%
KEV
⚠ Exploited

Published

October 5, 2021

Last Modified

February 17, 2026

Advisory Details (6)

Auto-updated May 27, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic

oss-security - Re: 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)

http://www.openwall.com/lists/oss-security/2021/10/08/3
generic

oss-security - Re: 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)

http://www.openwall.com/lists/oss-security/2021/10/08/2
generic

oss-security - Re: 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)

http://www.openwall.com/lists/oss-security/2021/10/08/1
generic

oss-security - 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)

http://www.openwall.com/lists/oss-security/2021/10/07/6
generic🔴 Active Exploitation

oss-security - RE: CVE-2021-41773: Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49

http://www.openwall.com/lists/oss-security/2021/10/07/1
generic🔴 Active Exploitation

oss-security - CVE-2021-41773: Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49

http://www.openwall.com/lists/oss-security/2021/10/05/2

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 61× in last 7d / 363× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 696 total refreshes for this CVE.

  1. 2026-07-24 14:15 UTCEPSS rescore
  2. 2026-07-23 02:04 UTCEG score recompute
  3. 2026-07-22 22:29 UTCEG score recompute
  4. 2026-07-22 22:29 UTCVendor advisory
  5. 2026-07-22 22:29 UTCGHSA enrichment
  6. 2026-07-22 19:40 UTCCISA KEV update
  7. 2026-07-22 18:46 UTCGHSA enrichment
  8. 2026-07-22 15:04 UTCVendor advisory
  9. 2026-07-22 15:04 UTCGHSA enrichment
  10. 2026-07-22 11:22 UTCVendor advisory
  11. 2026-07-22 11:22 UTCGHSA enrichment
  12. 2026-07-22 07:40 UTCVendor advisory
  13. 2026-07-22 07:40 UTCGHSA enrichment
  14. 2026-07-22 03:59 UTCVendor advisory
  15. 2026-07-22 03:59 UTCGHSA enrichment
  16. 2026-07-22 00:13 UTCVendor advisory
  17. 2026-07-22 00:13 UTCGHSA enrichment
  18. 2026-07-21 20:31 UTCVendor advisory
  19. 2026-07-21 20:31 UTCGHSA enrichment
  20. 2026-07-21 16:47 UTCVendor advisory
  21. 2026-07-21 16:47 UTCGHSA enrichment
  22. 2026-07-21 14:37 UTCCISA KEV update
  23. 2026-07-21 13:05 UTCVendor advisory
  24. 2026-07-21 13:05 UTCGHSA enrichment
  25. 2026-07-21 09:23 UTCVendor advisory
Show 75 more
  1. 2026-07-21 09:23 UTCGHSA enrichment
  2. 2026-07-21 05:41 UTCVendor advisory
  3. 2026-07-21 05:41 UTCGHSA enrichment
  4. 2026-07-21 01:58 UTCVendor advisory
  5. 2026-07-21 01:58 UTCGHSA enrichment
  6. 2026-07-20 22:17 UTCVendor advisory
  7. 2026-07-20 22:16 UTCGHSA enrichment
  8. 2026-07-20 18:34 UTCVendor advisory
  9. 2026-07-20 18:34 UTCGHSA enrichment
  10. 2026-07-20 14:53 UTCGHSA enrichment
  11. 2026-07-20 11:12 UTCGHSA enrichment
  12. 2026-07-20 07:30 UTCVendor advisory
  13. 2026-07-20 07:30 UTCGHSA enrichment
  14. 2026-07-20 03:49 UTCVendor advisory
  15. 2026-07-20 03:49 UTCGHSA enrichment
  16. 2026-07-20 00:07 UTCVendor advisory
  17. 2026-07-20 00:07 UTCGHSA enrichment
  18. 2026-07-19 20:26 UTCVendor advisory
  19. 2026-07-19 20:26 UTCGHSA enrichment
  20. 2026-07-19 16:44 UTCVendor advisory
  21. 2026-07-19 16:44 UTCGHSA enrichment
  22. 2026-07-19 13:02 UTCVendor advisory
  23. 2026-07-19 13:02 UTCGHSA enrichment
  24. 2026-07-19 09:21 UTCVendor advisory
  25. 2026-07-19 09:21 UTCGHSA enrichment
  26. 2026-07-19 05:39 UTCVendor advisory
  27. 2026-07-19 05:39 UTCGHSA enrichment
  28. 2026-07-19 01:57 UTCGHSA enrichment
  29. 2026-07-18 22:15 UTCVendor advisory
  30. 2026-07-18 22:14 UTCGHSA enrichment
  31. 2026-07-18 18:33 UTCVendor advisory
  32. 2026-07-18 18:33 UTCGHSA enrichment
  33. 2026-07-18 14:51 UTCVendor advisory
  34. 2026-07-18 14:51 UTCGHSA enrichment
  35. 2026-07-18 11:09 UTCVendor advisory
  36. 2026-07-18 11:09 UTCGHSA enrichment
  37. 2026-07-18 07:27 UTCVendor advisory
  38. 2026-07-18 07:27 UTCGHSA enrichment
  39. 2026-07-18 03:46 UTCVendor advisory
  40. 2026-07-18 03:46 UTCGHSA enrichment
  41. 2026-07-18 00:05 UTCVendor advisory
  42. 2026-07-18 00:04 UTCGHSA enrichment
  43. 2026-07-17 20:21 UTCVendor advisory
  44. 2026-07-17 20:21 UTCGHSA enrichment
  45. 2026-07-17 16:39 UTCVendor advisory
  46. 2026-07-17 16:39 UTCGHSA enrichment
  47. 2026-07-17 12:58 UTCVendor advisory
  48. 2026-07-17 12:57 UTCGHSA enrichment
  49. 2026-07-17 09:16 UTCEG score recompute
  50. 2026-07-17 09:16 UTCVendor advisory
  51. 2026-07-17 09:16 UTCGHSA enrichment
  52. 2026-07-17 05:34 UTCVendor advisory
  53. 2026-07-17 05:34 UTCGHSA enrichment
  54. 2026-07-17 01:52 UTCVendor advisory
  55. 2026-07-17 01:52 UTCGHSA enrichment
  56. 2026-07-16 22:11 UTCVendor advisory
  57. 2026-07-16 22:10 UTCGHSA enrichment
  58. 2026-07-16 18:28 UTCVendor advisory
  59. 2026-07-16 18:28 UTCGHSA enrichment
  60. 2026-07-16 17:04 UTCCISA KEV update
  61. 2026-07-16 14:46 UTCGHSA enrichment
  62. 2026-07-16 11:04 UTCVendor advisory
  63. 2026-07-16 11:04 UTCGHSA enrichment
  64. 2026-07-16 07:23 UTCVendor advisory
  65. 2026-07-16 07:23 UTCGHSA enrichment
  66. 2026-07-16 03:41 UTCVendor advisory
  67. 2026-07-16 03:41 UTCGHSA enrichment
  68. 2026-07-16 00:00 UTCVendor advisory
  69. 2026-07-16 00:00 UTCGHSA enrichment
  70. 2026-07-15 20:18 UTCVendor advisory
  71. 2026-07-15 20:18 UTCGHSA enrichment
  72. 2026-07-15 16:49 UTCCISA KEV update
  73. 2026-07-15 16:36 UTCVendor advisory
  74. 2026-07-15 16:36 UTCGHSA enrichment
  75. 2026-07-15 15:04 UTCCISA KEV update

Publicly available exploits

(10 references)

Working exploit code is in the public domain (8 GitHub PoCs) (2 Exploit-DB entries). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-50512✓ verified
    First seen Nov 11, 2021

    Apache HTTP Server 2.4.50 - Remote Code Execution (RCE) (3)

    Open source ↗
  • GitHub PoCMrCl0wnLab/SimplesApachePathTraversal
    First seen Oct 13, 2021

    Tool check: CVE-2021-41773, CVE-2021-42013, CVE-2020-17519

    Open source ↗
  • GitHub PoCinbug-team/CVE-2021-41773_CVE-2021-42013
    First seen Oct 9, 2021

    CVE-2021-41773 CVE-2021-42013漏洞批量检测工具

    Open source ↗
  • GitHub PoCim-hanzou/apachrot
    First seen Oct 9, 2021

    Apache (Linux) CVE-2021-41773/2021-42013 Mass Vulnerability Checker

    Open source ↗
  • GitHub PoCHightechSec/scarce-apache2
    First seen Oct 7, 2021

    A framework for bug hunting or pentesting targeting websites that have CVE-2021-41773 Vulnerability in public

    Open source ↗
  • GitHub PoCjustakazh/mass_cve-2021-41773
    First seen Oct 7, 2021

    MASS CVE-2021-41773

    Open source ↗
  • Exploit-DBEDB-50383✓ verified
    First seen Oct 6, 2021

    Apache HTTP Server 2.4.49 - Path Traversal & Remote Code Execution (RCE)

    Open source ↗
  • GitHub PoCblasty/CVE-2021-41773
    First seen Oct 6, 2021

    CVE-2021-41773 playground

    Open source ↗
  • GitHub PoCBlueTeamSteve/CVE-2021-41773
    First seen Oct 6, 2021

    Vulnerable docker images for CVE-2021-41773

    Open source ↗
  • GitHub PoCiilegacyyii/PoC-CVE-2021-41773
    First seen Oct 5, 2021
    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(6)

What is CVE-2021-41773?
CVE-2021-41773 is a critical vulnerability published on October 5, 2021. 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…
When was CVE-2021-41773 disclosed?
CVE-2021-41773 was first published in the National Vulnerability Database on October 5, 2021, with the most recent update on February 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-41773 actively exploited?
Yes. CISA added CVE-2021-41773 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Apache HTTP Server. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-41773?
CVE-2021-41773 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2021-41773?
CVE-2021-41773 affects Apache HTTP Server. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2021-41773?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-41773, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2021-41773

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