FastStone Image Viewer 1bpp RLE Decoder out-of-bounds write (CVE-2026-101203) | HOL Guard CVE

Medium · CVSS 5.3CVE-2026-101203

FastStone Image Viewer 1bpp RLE Decoder out-of-bounds write

Answer in brief

CVE-2026-101203 records a Medium severity (CVSS 5.3) vulnerability in FastStone Image Viewer 1bpp RLE Decoder out-of-bounds write. The current sources do not mark it as known exploited. The current feed maps FastStone/Image Viewer (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 28, 2026Updated Sep 28, 2026Source checked Sep 28, 2026First seen by HOL Sep 28, 2026Material review Sep 28, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.3
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps FastStone/Image Viewer (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
FastStone/Image Viewergeneric	8.0 \|\| 8.1 \|\| 8.2 \|\| 8.3	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for FastStone/Image Viewer.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 28, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.