CVE-2021-47970Public exploit

Application crash via oversized note input

Published May 16, 2026 · Updated May 16, 2026

Denial of service in Macaron Notes 5.5 allows attackers to crash the iOS application by pasting an excessively long string into a note. The note editor processes a 350,000-character payload without an effective length limit, leading to excessive memory allocation and application termination. Exploitation requires opening the app, creating a note, and pasting the generated text; the demonstrated consequence is interruption of the app's note-taking functionality.

CVSS severity8.7
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Macaron Notes 5.5 allows attackers to crash the iOS application by pasting an excessively long string into a note. The note editor processes a 350,000-character payload without an effective length limit, leading to excessive memory allocation and application termination. Exploitation requires opening the app, creating a note, and pasting the generated text; the demonstrated consequence is interruption of the app's note-taking functionality.

The record

CVE
CVE-2021-47970
Published
May 16, 2026
Updated
May 16, 2026
Vendor
Macaron Notes
Product
Macaron Notes
Classifications
CWE-789, T1642
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. May 16, 2026CVE publishedPublication date reported by the CVE source.
  2. May 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.5

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Macaron Notes · Macaron Notesversion=5.5

Published CVSS scores

8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
7.5VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-789Memory Allocation with Excessive Size Value
T1642Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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