# CVE-2026-45129: MyBB: ACP Recovery Codes CSRF

> Attackers can force administrators to regenerate two-factor authentication recovery codes via CSRF, potentially bypassing 2FA protections.

- **Severity:** Medium 4.6 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 18 Aug 2026
- **Updated:** 18 Aug 2026
- **Also known as:** GHSA-75vg-6wgp-mcc9

## What is CVE-2026-45129?

CVE-2026-45129 is a medium-severity vulnerability in mybb, published on 18 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

MyBB is free and open source forum software. Prior to 1.8.40, the Admin CP Recovery Codes module does not validate requests correctly, allowing same-site attackers to rotate a victim administrator's recovery codes with a specially crafted URL. The Admin CP Home, Preferences, Recovery Codes action=recovery_codes page regenerates Two-Factor Authentication recovery codes in mybb_adminoptions.recovery_codes on GET requests without request forgery protection. The uniquely identifying implementation details include admin/modules/home/preferences.php. This issue is fixed in version 1.8.40.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2026-45129?


## How do I fix CVE-2026-45129?

No fix has been published for CVE-2026-45129 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-45129 being exploited?

There is no known exploitation of CVE-2026-45129 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45129 and fix it if it is affected.

What it is: CVE-2026-45129 is a medium-severity vulnerability in mybb, published on 18 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-45129 in the wild and no public exploit code.

Affected product: mybb. 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-2026-45129/ (Markdown: https://insights.sbomify.com/CVE-2026-45129/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45129
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45129
- OSV: https://osv.dev/vulnerability/CVE-2026-45129

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45129/
Summaries are generated and may contain mistakes; the official description above is the record.