CVE-2021-47971

CVE-2021-47971 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-789.

Key facts

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.

Frequently asked questions

What is CVE-2021-47971?
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.
How severe is CVE-2021-47971?
CVE-2021-47971 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-47971 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2021-47971?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2021-47971 have an EU (EUVD) identifier?
Yes. CVE-2021-47971 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34828.
When was CVE-2021-47971 published?
CVE-2021-47971 was published on 2026-05-16 and last updated on 2026-06-17.

References

Other CWE-789 vulnerabilities

Browse all CWE-789 vulnerabilities →