PT-2021-16974 · Faststone · Faststone Image Viewer

Voidsec · Published 2021-03-18 · Updated 2021-03-22 · CVE-2021-26233

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

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

Name of the Vulnerable Software and Affected Versions FastStone Image Viewer versions <= 7.5

Description The issue is triggered when a user opens or views a malformed CUR file that is mishandled by FSViewer.exe, resulting in a user mode write access violation near NULL at 0x005bdfcb. This could be exploited for a Denial of Service (DoS) or possibly to achieve code execution.

Recommendations For FastStone Image Viewer versions <= 7.5, avoid opening or viewing malformed CUR files until a patch is available. As a temporary workaround, consider restricting the use of FSViewer.exe to minimize the risk of exploitation.

Fix

Memory Corruption

Weakness Enumeration

CWE-787

Related Identifiers

CVE-2021-26233

Affected Products

Faststone Image Viewer

References · 4

• https://nvd.nist.gov/vuln/detail/CVE-2021-26233 · Security Note
• https://osv.dev/vulnerability/CVE-2021-26233 · Vendor Advisory
• https://t.me/cibsecurity/25115 · Telegram Post
• https://voidsec.com/advisories/cve-2021-26233-faststone-image-viewer-v-7-5-user-mode-write-access-violation · Note