Junglewise Threat Intelligence

CVE-2021-47944: memono Notepad denial of service via excessive character input

CVE-2021-47944 · Severity: high · CVSS 7.5 · Published 2026-05-10

Technologies: Memono Notepad\+\+.

Executive brief

memono Notepad is a note-taking application for iOS devices. A vulnerability in version 4.2 allows the application to be crashed by pasting an extremely large amount of text into a note field. This results in a denial of service, making the application unusable until it is restarted or the problematic data is removed.

Technical details

A denial of service vulnerability exists in memono Notepad 4.2 for iOS due to improper handling of large memory allocations (CWE-789). The application fails to adequately validate the length of input when text is pasted into a note field. An attacker can trigger an application crash by pasting a buffer of approximately 700,000 characters (e.g., two instances of a 350,000-character string) into a new note. This local exploit was verified on iOS 14.2. While some sources list a network attack vector, the primary exploitation method requires local user interaction to paste the malicious payload.

Affected products

  • memono Notepad 4.2

Timeline

  • 2021-06-09: disclosed: Initial discovery and PoC by Geovanni Ruiz
  • 2026-05-10: advisory: NVD/VulnCheck advisory published

References