# CVE-2026-22189: Panda3D <= 1.10.16 egg-mkfont Stack Buffer Overflow

> Attacker can trigger stack buffer overflow in Panda3D egg-mkfont via long glyph patterns, potentially causing crashes or arbitrary code execution.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Jan 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-gwg6-62mc-7h63

## What is CVE-2026-22189?

CVE-2026-22189 is a medium-severity memory corruption vulnerability in Panda3D, published on 7 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The egg-mkfont utility in Panda3D versions up to and including 1.10.16 contains a stack-based buffer overflow vulnerability due to use of an unbounded sprintf() call with attacker-controlled input. When constructing glyph filenames, egg-mkfont formats a user-supplied glyph pattern (-gp) into a fixed-size stack buffer without length validation. Supplying an excessively long glyph pattern string can overflow the stack buffer, resulting in memory corruption and a deterministic crash. Depending on build configuration and execution environment, the overflow may also be exploitable for arbitrary code execution.

Weakness: CWE-787 (Out-of-bounds Write), CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2026-22189?

It affects 1 product.


Products: Cmu Panda3d.

## How do I fix CVE-2026-22189?

No fix has been published for CVE-2026-22189 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-22189 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-22189 exists.

## Other vulnerabilities in Panda3D

- [CVE-2026-22188](https://insights.sbomify.com/CVE-2026-22188/): Panda3D <= 1.10.16 Deploy-Stub Stack Exhaustion via Unbounded alloca() (medium 6.9)
- [CVE-2026-22190](https://insights.sbomify.com/CVE-2026-22190/): Panda3D <= 1.10.16 egg-mkfont Format String Information Disclosure (medium 5.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-22189 and fix it if it is affected.

What it is: CVE-2026-22189 is a medium-severity memory corruption vulnerability in Panda3D, published on 7 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-22189 exists.

Affected product: Panda3D. 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-2026-22189/ (Markdown: https://insights.sbomify.com/CVE-2026-22189/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22189
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22189
- OSV: https://osv.dev/vulnerability/CVE-2026-22189

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-22189/
Summaries are generated and may contain mistakes; the official description above is the record.