CVE-2020-35843

Name: CVE-2020-35843
Creator: NVD / NIST
Published: 2021-01-26T18:15:54.85+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.75%

Last modified Jun 17, 2026

CVE-2020-35843 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. FastStone Image Viewer 7.5 has an out-of-bounds write (via a crafted image file) at FSViewer.exe+0x956e.. EPSS estimates a 0.75% chance of exploitation in the next 30 days.

Description

FastStone Image Viewer 7.5 has an out-of-bounds write (via a crafted image file) at FSViewer.exe+0x956e.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS Probability

0.75%

50.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Faststone	Image Viewer	7.5

References

https://github.com/DmitryMeD/pentesting/blob/main/FastStone%20Image%20Viewer%207.5.mdExploit, Third Party Advisory
https://twitter.com/DmitriyMelikovThird Party Advisory
https://github.com/DmitryMeD/pentesting/blob/main/FastStone%20Image%20Viewer%207.5.mdExploit, Third Party Advisory
https://twitter.com/DmitriyMelikovThird Party Advisory

Timeline

Published: Jan 26, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-35843?

FastStone Image Viewer 7.5 has an out-of-bounds write (via a crafted image file) at FSViewer.exe+0x956e.

How severe is CVE-2020-35843?

CVE-2020-35843 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.75% probability of exploitation in the next 30 days.

How do I fix CVE-2020-35843?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-35843?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST