CVE-2021-47971

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-05-16. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

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

My Notes Safe 5.3 contains a denial of service vulnerability that allows attackers to crash the application by pasting excessively long character strings into note fields. Attackers can generate a payload containing 350000 repeated characters and paste it twice into a new note to trigger an application crash.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
20.3%
KEV
Not listed

Published

May 16, 2026

Last Modified

May 18, 2026

Advisory Details (2)

Auto-updated May 16, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic

My Notes Safe 5.3 Denial of Service via Buffer Overflow | Advisories | VulnCheck

https://www.vulncheck.com/advisories/my-notes-safe-denial-of-service-via-buffer-overflow
generic🟡 PoC Available

My Notes Safe 5.3 - Denial of Service (PoC) - iOS dos Exploit

https://www.exploit-db.com/exploits/49954

Vendor Advisories for CVE-2021-47971(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 78× 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 192 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2021-47971?
CVE-2021-47971 is a high vulnerability published on May 16, 2026. My Notes Safe 5.3 contains a denial of service vulnerability that allows attackers to crash the application by pasting excessively long character strings into note fields. Attackers can generate a payload containing 350000 repeated characters and paste it twice into a new note to trigger an…
When was CVE-2021-47971 disclosed?
CVE-2021-47971 was first published in the National Vulnerability Database on May 16, 2026, with the most recent update on May 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-47971 actively exploited?
CVE-2021-47971 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 20.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-47971?
CVE-2021-47971 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2021-47971?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-47971, 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

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