# CVE-2026-21339: Substance3D - Designer | Out-of-bounds Read (CWE-125)

> An out-of-bounds read in Adobe Substance 3D Designer allows attackers to disclose sensitive memory information by tricking users into opening malicious files.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 10 Feb 2026
- **Updated:** 27 Aug 2026
- **Also known as:** GHSA-5848-q9pf-4h9c

## What is CVE-2026-21339?

CVE-2026-21339 is a medium-severity vulnerability in Adobe Substance 3d Designer, published on 10 Feb 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Substance3D - Designer versions 15.1.0 and earlier are affected by an out-of-bounds read vulnerability that could lead to memory exposure. An attacker could leverage this vulnerability to disclose sensitive information stored in memory. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-21339?

It affects 1 product.


Products: Adobe Substance 3d Designer.

## How do I fix CVE-2026-21339?

No fix has been published for CVE-2026-21339 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-21339 being exploited?

There is no known exploitation of CVE-2026-21339 in the wild and no public exploit code.

## Other vulnerabilities in Adobe Substance 3d Designer

- [CVE-2026-103821](https://insights.sbomify.com/CVE-2026-103821/): Substance3D - Designer | Out-of-bounds Write (CWE-787) (high 7.8)
- [CVE-2026-48426](https://insights.sbomify.com/CVE-2026-48426/): Substance3D - Designer | Out-of-bounds Write (CWE-787) (high 7.8)
- [CVE-2026-48427](https://insights.sbomify.com/CVE-2026-48427/): Substance3D - Designer | Out-of-bounds Write (CWE-787) (high 7.8)
- [CVE-2026-48428](https://insights.sbomify.com/CVE-2026-48428/): Substance3D - Designer | Heap-based Buffer Overflow (CWE-122) (high 7.8)
- [CVE-2026-48430](https://insights.sbomify.com/CVE-2026-48430/): Substance3D - Designer | Heap-based Buffer Overflow (CWE-122) (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-21339 and fix it if it is affected.

What it is: CVE-2026-21339 is a medium-severity vulnerability in Adobe Substance 3d Designer, published on 10 Feb 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-21339 in the wild and no public exploit code.

Affected product: Adobe Substance 3d Designer. 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-2026-21339/ (Markdown: https://insights.sbomify.com/CVE-2026-21339/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-21339
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-21339
- OSV: https://osv.dev/vulnerability/CVE-2026-21339

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-21339/
Summaries are generated and may contain mistakes; the official description above is the record.