# CVE-2026-101205: FastStone Image Viewer PCX Decoder out-of-bounds

> An out-of-bounds read in the PCX decoder allows remote attackers to cause denial of service or disclose information via a malicious image file.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **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 available:** No
- **Published:** 28 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-pfm3-9fm2-9vx6

## What is CVE-2026-101205?

CVE-2026-101205 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 was determined in FastStone Image Viewer up to 8.3. This impacts an unknown function of the component PCX Decoder. This manipulation causes out-of-bounds read. The attack may be initiated remotely. The vendor was contacted early about this disclosure but did not respond in any way.

Weakness: CWE-125 (Out-of-bounds Read), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-101205?


## How do I fix CVE-2026-101205?

No fix has been published for CVE-2026-101205 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-101205 being exploited?

There is no known exploitation of CVE-2026-101205 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-101205 and fix it if it is affected.

What it is: CVE-2026-101205 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.
Exploitation: There is no known exploitation of CVE-2026-101205 in the wild and no public exploit code.

Affected product: FastStone Image Viewer. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-101205/ (Markdown: https://insights.sbomify.com/CVE-2026-101205/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101205
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101205
- OSV: https://osv.dev/vulnerability/CVE-2026-101205

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-101205/
Summaries are generated and may contain mistakes; the official description above is the record.