# CVE-2026-18216: Backup Migration < 2.1.7 - Admin+ Privilege Escalation via Post-Restore Auto-Login

> An administrator of one site in a WordPress multisite network can gain administrator access to another site via a flawed post-restore auto-login mechanism.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** GHSA-g4x6-qr8w-c3x7

## What is CVE-2026-18216?

CVE-2026-18216 is a medium-severity vulnerability in Unknown Backup Migration, published on 15 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

The Backup Migration WordPress plugin before 2.1.7 does not properly restrict a post-restore automatic login mechanism, allowing a user who administers one site of a multisite network to obtain a long-lived authenticated session as an administrator of another site in the same network, without credentials and bypassing two-factor authentication.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-18216?


## How do I fix CVE-2026-18216?

No fix has been published for CVE-2026-18216 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-18216 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-18216 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18216 and fix it if it is affected.

What it is: CVE-2026-18216 is a medium-severity vulnerability in Unknown Backup Migration, published on 15 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-18216 exists.

Affected product: Unknown Backup Migration. 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-2026-18216/ (Markdown: https://insights.sbomify.com/CVE-2026-18216/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18216
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18216
- OSV: https://osv.dev/vulnerability/CVE-2026-18216

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18216/
Summaries are generated and may contain mistakes; the official description above is the record.