CVE-2021-47971

HighPublic PoC

Published: 16 May 2026

Published

16 May 2026

Modified

18 May 2026

KEV Added

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Patch

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CVSS Score v4 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Score 0.0028 20.2th percentile

Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2021-47971 is a high-severity Memory Allocation with Excessive Size Value (CWE-789) vulnerability. Its CVSS base score is 8.7 (High).

Operationally, ranked at the 20.2th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2021-34828

Vulnerability details

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.