# CVE-2026-103087: Denial of service in gosub-engine

> Remote attackers can crash the Gosub browser engine via deeply nested SVG elements, causing stack exhaustion and denial of service.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **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:** 30 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** GHSA-c762-mxfh-vwvp, GHSA-pj55-j4f4-8jj5

## What is CVE-2026-103087?

CVE-2026-103087 is a high-severity denial of service vulnerability in gosub-io gosub-engine, published on 30 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

Uncontrolled recursion in the Gosub browser engine (gosub-engine) through 0.1.0 and main before commit 46868b3 allows a remote attacker to cause a Denial of Service (stack exhaustion and application crash) via an SVG document containing an excessive number of deeply nested elements. Because the engine does not limit the nesting depth of processed SVG nodes, rendering such a document overflows the thread stack and terminates the application. The malicious SVG can be embedded through the SRC attribute of an IMG element, and thus exploitation only requires the victim to visit an attacker-controlled web page.

Weakness: CWE-674 (Uncontrolled Recursion)

## Which versions are affected by CVE-2026-103087?


## How do I fix CVE-2026-103087?

No fix has been published for CVE-2026-103087 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-103087 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-103087 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103087 and fix it if it is affected.

What it is: CVE-2026-103087 is a high-severity denial of service vulnerability in gosub-io gosub-engine, published on 30 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-103087 exists.

Affected product: gosub-io gosub-engine. 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-2026-103087/ (Markdown: https://insights.sbomify.com/CVE-2026-103087/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103087
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103087
- OSV: https://osv.dev/vulnerability/CVE-2026-103087

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103087/
Summaries are generated and may contain mistakes; the official description above is the record.