# CVE-2026-73313: XenForo < 2.3.13 MFA Bypass via Passkey TFA Provider

> An authenticated attacker can bypass multi-factor authentication on XenForo by using their own passkey to log in as another user who knows the target's password.

- **Severity:** High 7.6 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/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:** 8 Sep 2026
- **Updated:** 1 Oct 2026
- **Also known as:** GHSA-wwh4-p7r6-v97f

## What is CVE-2026-73313?

CVE-2026-73313 is a high-severity authentication bypass vulnerability in XenForo, published on 8 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

XenForo before 2.3.13 contains a multi-factor authentication bypass vulnerability in the passkey TFA provider that allows an authenticated attacker to complete login as another user by submitting their own registered passkey credential during the WebAuthn assertion step. The passkey verification path performs a global credential lookup without validating that the matched credential belongs to the user whose login is pending, enabling an attacker who knows a target account's password to sign the challenge with their own passkey and bypass multi-factor authentication on both public forum and ACP login paths.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-73313?

It affects 1 product.


Products: Xenforo Xenforo.

## How do I fix CVE-2026-73313?

No fix has been published for CVE-2026-73313 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-73313 being exploited?

There is no known exploitation of CVE-2026-73313 in the wild and no public exploit code.

Public exploit code:

- Sanitized XenForo write-up and proof of concept for CVE-2026-73313. (github_poc): https://github.com/BomboBombone/CVE-2026-73313

## Other vulnerabilities in XenForo

- [CVE-2025-71279](https://insights.sbomify.com/CVE-2025-71279/): XenForo Passkey Security Bypass (critical 9.3)
- [CVE-2026-73309](https://insights.sbomify.com/CVE-2026-73309/): XenForo < 2.3.13 Authentication Bypass via OAuth2 Token Endpoint (critical 9.1)
- [CVE-2026-73311](https://insights.sbomify.com/CVE-2026-73311/): XenForo < 2.3.13 OAuth2 Authorization Code Reuse (critical 9.1)
- [CVE-2026-73312](https://insights.sbomify.com/CVE-2026-73312/): XenForo < 2.3.13 Refresh Token Replay via Expired Access Token (critical 9.1)
- [CVE-2024-38457](https://insights.sbomify.com/CVE-2024-38457/): Xenforo before 2.2.16 allows CSRF. (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-73313 and fix it if it is affected.

What it is: CVE-2026-73313 is a high-severity authentication bypass vulnerability in XenForo, published on 8 Sep 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-2026-73313 in the wild and no public exploit code.

Affected product: XenForo. 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-2026-73313/ (Markdown: https://insights.sbomify.com/CVE-2026-73313/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-73313
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-73313
- OSV: https://osv.dev/vulnerability/CVE-2026-73313

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-73313/
Summaries are generated and may contain mistakes; the official description above is the record.