CVE-2021-47971

HIGH

My Notes Safe 5.3 Denial of Service via Buffer Overflow

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-47971. PoCs published by Geovanni Ruiz.

AI-analyzed exploit summary This PoC demonstrates a DoS vulnerability in My Notes Safe 5.3 by generating a large payload (350,000 'A' characters) that crashes the application when pasted into a note. The exploit is straightforward and targets a buffer overflow or memory handling issue in the iOS app.

Description

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.

Exploits (1)

exploitdb WORKING POC
by Geovanni Ruiz · pythondosios
https://www.exploit-db.com/exploits/49954

This PoC demonstrates a DoS vulnerability in My Notes Safe 5.3 by generating a large payload (350,000 'A' characters) that crashes the application when pasted into a note. The exploit is straightforward and targets a buffer overflow or memory handling issue in the iOS app.

Classification
Working Poc 90%
Attack Type
Dos
Complexity
Trivial
Reliability
Reliable
Target: My Notes Safe 5.3 (iOS)
No auth needed
Prerequisites: My Notes Safe 5.3 installed on iOS · ability to create a new note
devstral-2 · analyzed May 16, 2026 Full analysis →

References (2)

Core 2
Core References
Exploit exploit
ExploitDB-49954
https://www.exploit-db.com/exploits/49954
Third Party Advisory third-party-advisory
VulnCheck Advisory: My Notes Safe 5.3 Denial of Service via Buffer Overflow
https://www.vulncheck.com/advisories/my-notes-safe-denial-of-service-via-buffer-overflow

Scores

CVSS v3 7.5
EPSS 0.0028
EPSS Percentile 19.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-789
Status published
Products (1)
my-notes-safe/My Notes Safe 5.3
Published May 16, 2026
Tracked Since May 16, 2026