CVE-2026-101203 FastStone Image Viewer 1bpp RLE Decoder out-of-bounds write
Remote attackers can trigger an out-of-bounds write in the 1bpp RLE decoder, potentially leading to arbitrary code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-101203?
CVE-2026-101203 is a medium-severity memory corruption vulnerability in FastStone Image Viewer, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
A vulnerability has been found in FastStone Image Viewer up to 8.3. The impacted element is an unknown function of the component 1bpp RLE Decoder. The manipulation leads to out-of-bounds write. The attack can be initiated remotely. The vendor was contacted early about this disclosure but did not respond in any way.
Which versions are affected by CVE-2026-101203?
How do I fix CVE-2026-101203?
No fix has been published for CVE-2026-101203 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-101203 being exploited?
There is no known exploitation of CVE-2026-101203 in the wild and no public exploit code.
Sources
Also known as GHSA-r4jh-4qvm-8mh5.