# eduMFA token reuse via incorrect InnoDB snapshot isolation

Source: https://junglewise.ai/threats/edumfa-token-reuse-via-incorrect-innodb-snapshot-isolation-7bd81af6  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-18. Updated: 2026-05-18  
License: CC BY 4.0 with a link back

Severity: high · CVSS 7.1 · Published 2026-05-18

eduMFA is a multi-factor authentication (MFA) solution. A vulnerability in how it handles database transactions could allow an attacker to reuse one-time security tokens (like TOTP or HOTP) that should expire after a single use. This could potentially allow an unauthorized user to bypass authentication protections if they can successfully time their requests during a login attempt.

Technologies: [edumfa (PyPI)](https://junglewise.ai/threats/technologies/edumfa). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** High severity, with a CVSS score of 7.1, published 18 May 2026.

**Which products and versions are affected?** edumfa (PyPI) < 2.9.1.

**Is there a fix for This vulnerability?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is This vulnerability attacked?** It is attacked over the network, in a software library.

**Am I affected?** Check whether you run edumfa (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A race condition exists in eduMFA due to incorrect InnoDB snapshot isolation when using MySQL or certain versions of MariaDB. The application fails to properly isolate database transactions, which can allow a single-use token (TOTP, HOTP, or WebAuthn) to be validated multiple times if multiple authentication requests are processed simultaneously. This occurs when 'innodb_snapshot_isolation' is disabled or unavailable in the underlying database. The vulnerability is fixed in version 2.9.1 by implementing explicit row-level locking using 'SELECT FOR UPDATE' before performing write operations. A database-level workaround involves enabling 'innodb_snapshot_isolation' where supported.

## Affected products

- eduMFA eduMFA < 2.9.1

## Timeline

- 2026-05-11: disclosed
- 2026-05-18: advisory

## References

- [https://github.com/eduMFA/eduMFA/security/advisories/GHSA-qq2p-4282-cfc5](https://github.com/eduMFA/eduMFA/security/advisories/GHSA-qq2p-4282-cfc5)
- [https://api.github.com/repos/eduMFA/eduMFA/security-advisories/GHSA-qq2p-4282-cfc5](https://api.github.com/repos/eduMFA/eduMFA/security-advisories/GHSA-qq2p-4282-cfc5)

## Related threats

- [eduMFA insufficient session expiration in Passkey challenges](https://junglewise.ai/threats/edumfa-insufficient-session-expiration-in-passkey-challenges-45557252)
- [eduMFA denial of service via failcounter increment in /validate/check](https://junglewise.ai/threats/edumfa-denial-of-service-via-failcounter-increment-in-validate-check-07905580)
- [BlastRADIUS also affects eduMFA](https://junglewise.ai/threats/blastradius-also-affects-edumfa-d5a0757e)