# CVE-2026-28557: wpForo Forum < 2.4.16 Privilege Escalation via Role Synchronization Handler

> Authenticated users can escalate privileges by remapping wpForo usergroups to arbitrary WordPress roles via a missing capability check.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Feb 2026
- **Updated:** 25 May 2026
- **Also known as:** GHSA-gfm6-fcx7-chmc

## What is CVE-2026-28557?

CVE-2026-28557 is a high-severity vulnerability in gVectors Team wpForo Forum, published on 28 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

wpForo Forum 2.4.14 contains a missing capability check vulnerability that allows authenticated users to trigger bulk wpForo usergroup reassignment via the wpforo_synch_roles AJAX handler. Attackers access the usergroups admin page, accessible to any authenticated user, to obtain a nonce, then remap all wpForo usergroups to arbitrary WordPress roles.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-28557?

It affects 1 product.


Products: Gvectors Wpforo Forum.

## How do I fix CVE-2026-28557?

No fix has been published for CVE-2026-28557 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-28557 being exploited?

There is no known exploitation of CVE-2026-28557 in the wild and no public exploit code.

## Other vulnerabilities in gVectors Team wpForo Forum

- [CVE-2024-3200](https://insights.sbomify.com/CVE-2024-3200/): wpForo Forum <= 2.3.3 - Authenticated (Contributor+) SQL Injection (critical 9.9)
- [CVE-2022-40200](https://insights.sbomify.com/CVE-2022-40200/): WordPress wpForo Forum plugin <= 2.0.9 - Auth. Arbitrary File Upload vulnerability (critical 9.9)
- [CVE-2018-16613](https://insights.sbomify.com/CVE-2018-16613/): Privilege escalation in n/a (critical 9.8)
- [CVE-2026-28562](https://insights.sbomify.com/CVE-2026-28562/): wpForo Forum 2.4.14 SQL Injection via Topics ORDER BY Parameter (high 8.8)
- [CVE-2023-2249](https://insights.sbomify.com/CVE-2023-2249/): Server-side request forgery in wpForo Forum (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-28557 and fix it if it is affected.

What it is: CVE-2026-28557 is a high-severity vulnerability in gVectors Team wpForo Forum, published on 28 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-28557 in the wild and no public exploit code.

Affected product: gVectors Team wpForo Forum. 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-2026-28557/ (Markdown: https://insights.sbomify.com/CVE-2026-28557/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-28557
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-28557
- OSV: https://osv.dev/vulnerability/CVE-2026-28557

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-28557/
Summaries are generated and may contain mistakes; the official description above is the record.