CVE-2021-33558

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
7.5EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 12%CVSS: 7.5Exploit: Elevated riskExposed services: Not assessed

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

Boa 0.94.13 allows remote attackers to obtain sensitive information via a misconfiguration involving backup.html, preview.html, js/log.js, log.html, email.html, online-users.html, and config.js. NOTE: multiple third parties report that this is a site-specific issue because those files are not part of Boa.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
50
EG Risk 50/100CISA 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
Severity75% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
12%
EPSS %ILE
96th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). 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

May 27, 2021

Last Modified

November 21, 2024

References (6)

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 29× 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 150 total refreshes for this CVE.

  1. 2026-10-05 17:40 UTCEPSS rescore
  2. 2026-10-03 14:22 UTCEPSS rescore
  3. 2026-10-01 19:46 UTCEPSS rescore
  4. 2026-09-30 15:36 UTCEG score recompute
  5. 2026-09-30 15:00 UTCEPSS rescore
  6. 2026-09-29 15:15 UTCEPSS rescore
  7. 2026-09-27 13:41 UTCEPSS rescore
  8. 2026-09-26 15:54 UTCEPSS rescore
  9. 2026-09-26 00:21 UTCEPSS rescore
  10. 2026-09-24 14:00 UTCEPSS rescore
  11. 2026-09-23 13:44 UTCEPSS rescore
  12. 2026-09-22 14:44 UTCEPSS rescore
  13. 2026-09-21 20:28 UTCEPSS rescore
  14. 2026-09-21 20:28 UTCEPSS rescore
  15. 2026-09-19 15:38 UTCEPSS rescore
  16. 2026-09-18 19:23 UTCEPSS rescore
  17. 2026-09-17 19:23 UTCEPSS rescore
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  19. 2026-09-16 14:05 UTCEPSS rescore
  20. 2026-09-16 14:05 UTCEPSS rescore
  21. 2026-09-15 03:06 UTCEPSS rescore
  22. 2026-09-13 16:43 UTCEPSS rescore
  23. 2026-09-12 14:57 UTCEPSS rescore
  24. 2026-09-11 14:49 UTCEPSS rescore
  25. 2026-09-11 09:33 UTCEPSS rescore
Show 75 more
  1. 2026-09-08 21:56 UTCEPSS rescore
  2. 2026-09-07 15:58 UTCEPSS rescore
  3. 2026-09-06 13:45 UTCEPSS rescore
  4. 2026-09-06 13:45 UTCEPSS rescore
  5. 2026-09-05 15:25 UTCEPSS rescore
  6. 2026-09-04 13:57 UTCEPSS rescore
  7. 2026-09-04 05:03 UTCEPSS rescore
  8. 2026-09-02 14:08 UTCEPSS rescore
  9. 2026-09-01 13:50 UTCEPSS rescore
  10. 2026-09-01 03:32 UTCEPSS rescore
  11. 2026-08-30 19:14 UTCEPSS rescore
  12. 2026-08-30 01:19 UTCEPSS rescore
  13. 2026-08-30 01:19 UTCEPSS rescore
  14. 2026-08-28 21:37 UTCEPSS rescore
  15. 2026-08-27 14:22 UTCEPSS rescore
  16. 2026-08-26 14:42 UTCEPSS rescore
  17. 2026-08-25 13:46 UTCEPSS rescore
  18. 2026-08-24 14:13 UTCEPSS rescore
  19. 2026-08-23 00:16 UTCEPSS rescore
  20. 2026-08-21 23:46 UTCEPSS rescore
  21. 2026-08-20 22:52 UTCEPSS rescore
  22. 2026-08-19 17:01 UTCEPSS rescore
  23. 2026-08-18 13:45 UTCEPSS rescore
  24. 2026-08-16 14:53 UTCEPSS rescore
  25. 2026-08-16 02:11 UTCEPSS rescore
  26. 2026-08-16 02:11 UTCEPSS rescore
  27. 2026-08-15 01:27 UTCEPSS rescore
  28. 2026-08-13 21:57 UTCEPSS rescore
  29. 2026-08-12 13:48 UTCEPSS rescore
  30. 2026-08-11 13:38 UTCEPSS rescore
  31. 2026-08-09 13:44 UTCEPSS rescore
  32. 2026-08-08 16:33 UTCEPSS rescore
  33. 2026-08-07 16:24 UTCEPSS rescore
  34. 2026-08-06 13:43 UTCEPSS rescore
  35. 2026-08-05 19:14 UTCEPSS rescore
  36. 2026-08-04 15:06 UTCEPSS rescore
  37. 2026-08-04 10:34 UTCEPSS rescore
  38. 2026-08-02 02:24 UTCEPSS rescore
  39. 2026-08-02 02:24 UTCEPSS rescore
  40. 2026-08-01 04:13 UTCEPSS rescore
  41. 2026-07-30 16:25 UTCEPSS rescore
  42. 2026-07-30 01:28 UTCEPSS rescore
  43. 2026-07-28 15:33 UTCEPSS rescore
  44. 2026-07-26 14:52 UTCEPSS rescore
  45. 2026-07-26 14:52 UTCEPSS rescore
  46. 2026-07-25 14:15 UTCEPSS rescore
  47. 2026-07-24 14:15 UTCEPSS rescore
  48. 2026-07-23 14:16 UTCEPSS rescore
  49. 2026-07-23 14:16 UTCEPSS rescore
  50. 2026-07-23 02:01 UTCEG score recompute
  51. 2026-07-22 22:48 UTCEG score recompute
  52. 2026-07-22 14:06 UTCEPSS rescore
  53. 2026-07-22 14:06 UTCEPSS rescore
  54. 2026-07-21 15:22 UTCEPSS rescore
  55. 2026-07-21 15:22 UTCEPSS rescore
  56. 2026-07-20 17:05 UTCEPSS rescore
  57. 2026-07-19 14:29 UTCEPSS rescore
  58. 2026-07-19 14:29 UTCEPSS rescore
  59. 2026-07-19 02:27 UTCEPSS rescore
  60. 2026-07-18 10:02 UTCEPSS rescore
  61. 2026-07-18 10:02 UTCEPSS rescore
  62. 2026-07-16 17:00 UTCEPSS rescore
  63. 2026-07-16 17:00 UTCEPSS rescore
  64. 2026-07-15 16:55 UTCEPSS rescore
  65. 2026-07-15 01:58 UTCEPSS rescore
  66. 2026-07-13 22:27 UTCEPSS rescore
  67. 2026-07-13 06:10 UTCEPSS rescore
  68. 2026-07-12 05:44 UTCEPSS rescore
  69. 2026-07-12 05:44 UTCEPSS rescore
  70. 2026-07-11 08:25 UTCEPSS rescore
  71. 2026-07-11 08:25 UTCEPSS rescore
  72. 2026-07-09 19:07 UTCEPSS rescore
  73. 2026-07-08 15:12 UTCEPSS rescore
  74. 2026-07-07 13:43 UTCEPSS rescore
  75. 2026-07-06 16:25 UTCEPSS rescore

Publicly available exploits

(2 references)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCmdanzaruddin/CVE-2021-33558.
    First seen May 25, 2021
    Open source ↗
  • Nucleihttp/cves/2021/CVE-2021-33558.yaml
    First seen Jan 1, 2021

    Boa 0.94.13 - Information Disclosure

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-33558?
CVE-2021-33558 is a high vulnerability published on May 27, 2021. Boa 0.94.13 allows remote attackers to obtain sensitive information via a misconfiguration involving backup.html, preview.html, js/log.js, log.html, email.html, online-users.html, and config.js. NOTE: multiple third parties report that this is a site-specific issue because those files are not part…
When was CVE-2021-33558 disclosed?
CVE-2021-33558 was first published on May 27, 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-2021-33558 actively exploited?
CVE-2021-33558 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 12% probability of exploitation in the next 30 days (96th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-33558?
CVE-2021-33558 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2021-33558?
No fix for CVE-2021-33558 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix.

Dependency Blast Radius

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