CVE-2021-21359

MEDIUMNVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.9 under NVD CVSS v3. EPSS exploit probability: 1.7% (76th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1.7%CVSS: 5.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 9.5.25, 10.4.14, 11.1.1 requesting invalid or non-existing resources via HTTP triggers the page error handler which again could retrieve content to be shown as error message from another page. This leads to a scenario in which the application is calling itself recursively - amplifying the impact of the initial attack until the limits of the web server are exceeded. This is fixed in versions 9.5.25, 10.4.14, 11.1.1.

CVSS v3
5.9
EG Score
5.9MEDIUMmedium confidence
EG Risk
32
EG Risk 32/100CISA SSVC

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
Severity59% × 45%
Exploitation2% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
1.7%
EPSS %ILE
76th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

March 23, 2021

Last Modified

November 21, 2024

References (6)

Affected Packages

(2 across 1 ecosystem)
Packagist(2)
PackageVulnerable rangeFix by version rangeDependents
typo3/cmsv9.0.0 ... v9.5.9 (34 versions)
  • 10.0.0 up to 10.4.14: fixed in 10.4.14
  • 11.0.0 up to 11.1.1: fixed in 11.1.1
  • 9.0.0 up to 9.5.25: fixed in 9.5.25
—
typo3/cms-corev9.0.0 ... v9.5.9 (34 versions)
  • 10.0.0 up to 10.4.14: fixed in 10.4.14
  • 11.0.0 up to 11.1.1: fixed in 11.1.1
  • 9.0.0 up to 9.5.25: fixed in 9.5.25
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 32× 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 183 total refreshes for this CVE.

  1. 2026-10-09 20:04 UTCEPSS rescore
  2. 2026-10-08 16:39 UTCEPSS rescore
  3. 2026-10-07 23:44 UTCEPSS rescore
  4. 2026-10-06 15:13 UTCEPSS rescore
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  10. 2026-10-01 19:46 UTCEPSS rescore
  11. 2026-09-30 15:29 UTCEG score recompute
  12. 2026-09-30 15:00 UTCEPSS rescore
  13. 2026-09-28 13:47 UTCEPSS rescore
  14. 2026-09-27 13:41 UTCEPSS rescore
  15. 2026-09-26 15:54 UTCEPSS rescore
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  17. 2026-09-26 06:55 UTCOSV refresh
  18. 2026-09-26 00:21 UTCEPSS rescore
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  21. 2026-09-23 13:44 UTCEPSS rescore
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  24. 2026-09-19 15:37 UTCEPSS rescore
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  1. 2026-09-17 19:23 UTCEPSS rescore
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  5. 2026-09-13 16:43 UTCEPSS rescore
  6. 2026-09-12 14:57 UTCEPSS rescore
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  9. 2026-09-08 21:56 UTCEPSS rescore
  10. 2026-09-07 15:58 UTCEPSS rescore
  11. 2026-09-06 21:01 UTCOSV refresh
  12. 2026-09-06 13:44 UTCEPSS rescore
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  20. 2026-08-30 19:14 UTCEPSS rescore
  21. 2026-08-30 01:19 UTCEPSS rescore
  22. 2026-08-28 21:37 UTCEPSS rescore
  23. 2026-08-27 14:22 UTCEPSS rescore
  24. 2026-08-26 14:42 UTCEPSS rescore
  25. 2026-08-25 13:45 UTCEPSS rescore
  26. 2026-08-23 00:16 UTCEPSS rescore
  27. 2026-08-21 23:46 UTCEPSS rescore
  28. 2026-08-20 22:52 UTCEPSS rescore
  29. 2026-08-20 06:55 UTCOSV refresh
  30. 2026-08-19 17:01 UTCEPSS rescore
  31. 2026-08-18 13:45 UTCEPSS rescore
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  39. 2026-08-09 13:43 UTCEPSS rescore
  40. 2026-08-08 16:33 UTCEPSS rescore
  41. 2026-08-07 16:23 UTCEPSS rescore
  42. 2026-08-06 13:43 UTCEPSS rescore
  43. 2026-08-05 19:14 UTCEPSS rescore
  44. 2026-08-05 02:10 UTCOSV refresh
  45. 2026-08-04 15:06 UTCEPSS rescore
  46. 2026-08-04 10:34 UTCEPSS rescore
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  48. 2026-08-02 02:24 UTCEPSS rescore
  49. 2026-08-01 04:12 UTCEPSS rescore
  50. 2026-07-30 16:25 UTCEPSS rescore
  51. 2026-07-30 01:27 UTCEPSS rescore
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  53. 2026-07-26 14:52 UTCEPSS rescore
  54. 2026-07-25 14:15 UTCEPSS rescore
  55. 2026-07-24 14:15 UTCEPSS rescore
  56. 2026-07-23 14:15 UTCEPSS rescore
  57. 2026-07-23 01:57 UTCEG score recompute
  58. 2026-07-22 22:43 UTCEG score recompute
  59. 2026-07-22 14:05 UTCEPSS rescore
  60. 2026-07-21 15:22 UTCEPSS rescore
  61. 2026-07-21 15:22 UTCEPSS rescore
  62. 2026-07-20 17:04 UTCEPSS rescore
  63. 2026-07-19 14:28 UTCEPSS rescore
  64. 2026-07-19 02:26 UTCEPSS rescore
  65. 2026-07-18 23:59 UTCOSV refresh
  66. 2026-07-18 10:02 UTCEPSS rescore
  67. 2026-07-16 17:00 UTCEPSS rescore
  68. 2026-07-15 16:55 UTCEPSS rescore
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  70. 2026-07-15 01:57 UTCEPSS rescore
  71. 2026-07-13 22:27 UTCEPSS rescore
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  73. 2026-07-13 06:10 UTCEPSS rescore
  74. 2026-07-13 06:10 UTCEPSS rescore
  75. 2026-07-12 05:44 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2021-21359?
CVE-2021-21359 is a medium vulnerability published on March 23, 2021. TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 9.5.25, 10.4.14, 11.1.1 requesting invalid or non-existing resources via HTTP triggers the page error handler which again could retrieve content to be shown as error message from another page. This leads to a…
When was CVE-2021-21359 disclosed?
CVE-2021-21359 was first published on March 23, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-21359 actively exploited?
CVE-2021-21359 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.7% probability of exploitation in the next 30 days (76th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-21359?
CVE-2021-21359 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2021-21359?
A fix for CVE-2021-21359 is available: update to the fixed version the vendor names in its advisory.

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