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Vulnerability record · CVE-2021-26233 · published 18 March 2021

CVE-2021-26233: Faststone image viewer out-of-bounds write vulnerability

Faststone · Image Viewer

FastStone Image Viewer <= 7.5 is affected by a user mode write access violation near NULL at 0x005bdfcb, triggered when a user opens or views a malformed CUR file that is mishandled by FSViewer.exe. Attackers could exploit this issue for a Denial of Service (DoS) or possibly to achieve code execution.

7.8 CVSS 3.1 High EPSS 1.1% · top 36.7% CWE-787 · Out-of-bounds write
7.8CVSS 3.1 base score, v2 6.8
1.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

FastStone Image Viewer <= 7.5 is affected by a user mode write access violation near NULL at 0x005bdfcb, triggered when a user opens or views a malformed CUR file that is mishandled by FSViewer.exe. Attackers could exploit this issue for a Denial of Service (DoS) or possibly to achieve code execution.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://voidsec.com/advisories/cve-2021-26233-faststone-image-viewer-v-7-5-user-mode-write-access-violation/ Third Party Advisory
https://voidsec.com/advisories/cve-2021-26233-faststone-image-viewer-v-7-5-user-mode-write-access-violation/ Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-26233), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.