CVE-2021-26236

Name: CVE-2021-26236
Creator: NVD / NIST
Published: 2021-03-18T13:15:20.393+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 1.97%

Last modified Jun 17, 2026

CVE-2021-26236 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. FastStone Image Viewer v.<= 7.5 is affected by a Stack-based Buffer Overflow at 0x005BDF49, affecting the CUR file parsing functionality (BITMAPINFOHEADER Structure, 'BitCount' file format field), that will end up corrupting the Structure Exception Handler (SEH). Attackers could exploit this issue to achieve code execution when a user opens or views a malformed/specially crafted CUR file.. EPSS estimates a 1.97% chance of exploitation in the next 30 days.

Description

FastStone Image Viewer v.<= 7.5 is affected by a Stack-based Buffer Overflow at 0x005BDF49, affecting the CUR file parsing functionality (BITMAPINFOHEADER Structure, 'BitCount' file format field), that will end up corrupting the Structure Exception Handler (SEH). Attackers could exploit this issue to achieve code execution when a user opens or views a malformed/specially crafted CUR file.

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

1.97%

77.9th 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://voidsec.com/advisories/cve-2021-26236-faststone-image-viewer-v-7-5-stack-based-buffer-overflow/Exploit, Third Party Advisory
https://voidsec.com/fuzzing-faststone-image-viewer-cve-2021-26236Exploit, Third Party Advisory
https://www.exploit-db.com/exploits/49660Exploit, Third Party Advisory, VDB Entry
https://voidsec.com/advisories/cve-2021-26236-faststone-image-viewer-v-7-5-stack-based-buffer-overflow/Exploit, Third Party Advisory
https://voidsec.com/fuzzing-faststone-image-viewer-cve-2021-26236Exploit, Third Party Advisory
https://www.exploit-db.com/exploits/49660Exploit, Third Party Advisory, VDB Entry

Timeline

Published: Mar 18, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-26236?

How severe is CVE-2021-26236?

CVE-2021-26236 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 1.97% probability of exploitation in the next 30 days.

How do I fix CVE-2021-26236?

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-2021-26236?

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

Scan your code now

Source: NVD / NIST