# CVE-2026-76731: Authentication Bypass in the Captive Portal of HPE Networking Instant On

> Unauthenticated attackers can bypass captive portal authentication to access and modify limited data in HPE Instant On devices.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** GHSA-6g54-w9r4-mw9h

## What is CVE-2026-76731?

CVE-2026-76731 is a medium-severity authentication bypass vulnerability in Hewlett Packard Enterprise (HPE) Instant ON, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An authentication bypass vulnerability in the captive portal of HPE Networking Instant On could allow an unauthenticated remote attacker to circumvent existing authentication controls. Successful exploitation could allow an attacker to gain limited access to some data and to make limited changes within the affected component.

Weakness: CWE-269 (Improper Privilege Management)

## Which versions are affected by CVE-2026-76731?


## How do I fix CVE-2026-76731?

No fix has been published for CVE-2026-76731 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-76731 being exploited?

There is no known exploitation of CVE-2026-76731 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-76731 and fix it if it is affected.

What it is: CVE-2026-76731 is a medium-severity authentication bypass vulnerability in Hewlett Packard Enterprise (HPE) Instant ON, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-76731 in the wild and no public exploit code.

Affected product: Hewlett Packard Enterprise (HPE) Instant ON. 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-2026-76731/ (Markdown: https://insights.sbomify.com/CVE-2026-76731/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-76731
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-76731
- OSV: https://osv.dev/vulnerability/CVE-2026-76731

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-76731/
Summaries are generated and may contain mistakes; the official description above is the record.