# CVE-2026-86306: light0011 cms Cookie Helper UserModel.class.php improper authentication

> Remote attackers can bypass authentication in light0011 CMS by manipulating the Username argument in the Cookie Helper, potentially leading to account takeover.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Sep 2026
- **Updated:** 8 Sep 2026
- **Also known as:** GHSA-3672-84c4-cx98

## What is CVE-2026-86306?

CVE-2026-86306 is a medium-severity authentication bypass vulnerability in light0011 cms, published on 7 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A weakness has been identified in light0011 cms c774dce31c6df0055568a8d5c53d964d99be199d/f72cf46f601efb2a0618c3814cc2f61380b38930. This affects an unknown part of the file App/Home/Model/UserModel.class.php of the component Cookie Helper. Executing a manipulation of the argument Username can lead to improper authentication. The attack may be performed from remote. The exploit has been made available to the public and could be used for attacks. This product utilizes a rolling release system for continuous delivery, and as such, version information for affected or updated releases is not disclosed. The project was informed of the problem early through an issue report but has not responded yet.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-86306?


## How do I fix CVE-2026-86306?

No fix has been published for CVE-2026-86306 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-86306 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86306 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-86306 and fix it if it is affected.

What it is: CVE-2026-86306 is a medium-severity authentication bypass vulnerability in light0011 cms, published on 7 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86306 exists.

Affected product: light0011 cms. 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-2026-86306/ (Markdown: https://insights.sbomify.com/CVE-2026-86306/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-86306
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-86306
- OSV: https://osv.dev/vulnerability/CVE-2026-86306

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-86306/
Summaries are generated and may contain mistakes; the official description above is the record.