# CVE-2026-91409: Vulnerability in Oracle Java SE (component: Networking).


- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 20 Oct 2026
- **Updated:** 23 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-91409, GHSA-5r5x-j567-5823, UBUNTU-CVE-2026-91409

## What is CVE-2026-91409?

CVE-2026-91409 is a low-severity vulnerability in Oracle Java SE, published on 20 Oct 2026. 

### Official description

Vulnerability in Oracle Java SE (component: Networking).   The supported version that is affected is Oracle Java SE: 27. Difficult to exploit vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Oracle Java SE.  Successful attacks of this vulnerability can result in unauthorized ability to cause a partial denial of service (partial DOS) of Oracle Java SE. Note: This vulnerability can be exploited by using APIs in the specified Component, e.g., through a web service which supplies data to the APIs. This vulnerability also applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. CVSS 3.1 Base Score 3.7 (Availability impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L).

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-91409?


## How do I fix CVE-2026-91409?

No fix has been published for CVE-2026-91409 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-91409 being exploited?

There is no known exploitation of CVE-2026-91409 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-91409 and fix it if it is affected.

What it is: CVE-2026-91409 is a low-severity vulnerability in Oracle Java SE, published on 20 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-91409 in the wild and no public exploit code.

Affected product: Oracle Java SE. 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-2026-91409/ (Markdown: https://insights.sbomify.com/CVE-2026-91409/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-91409
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-91409
- OSV: https://osv.dev/vulnerability/CVE-2026-91409

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-91409/
Summaries are generated and may contain mistakes; the official description above is the record.