# CVE-2026-72584: FastSchema TOCTOU race condition in OTP account recovery

Source: https://junglewise.ai/threats/cve-2026-72584-fastschema-toctou-race-condition-in-otp-account-recovery  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-10. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-72584 · Severity: high · CVSS 7.4 · Published 2026-08-10

FastSchema is a backend-as-a-service platform with headless CMS capabilities used to manage application data and content. A timing flaw in the account recovery flow allows attackers to bypass protections against repeated incorrect OTP attempts, enabling brute-force attacks against 6-digit one-time passwords without authentication. This could allow an attacker to gain unauthorized access to user accounts.

Technologies: [Fastschema](https://junglewise.ai/threats/technologies/fastschema). Vendors: [Fastschema](https://junglewise.ai/threats/vendors/fastschema).

## Quick answers

**Is CVE-2026-72584 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-72584 being exploited in the wild.

**How severe is CVE-2026-72584?** High severity, with a CVSS score of 7.4, published 10 August 2026.

**Which products and versions are affected?** Fastschema through v0.15.1.

**Is there a fix for CVE-2026-72584?** 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 CVE-2026-72584 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-72584?** Check whether you run Fastschema 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 time-of-check/time-of-use (TOCTOU) race condition exists in the account recovery OTP validation logic in FastSchema through v0.15.1. The vulnerability allows an unauthenticated remote attacker to bypass rate-limiting or attempt-count restrictions on OTP verification by exploiting a window between when the system checks the attempt limit and when it increments the counter. An attacker can rapidly submit multiple OTP guesses from different requests to brute-force 6-digit codes (1 million possibilities) before the limit is enforced. No authentication is required; the attack is triggered over the network during account recovery. A patch is expected in later versions beyond v0.15.1.

## Affected products

- FastSchema FastSchema through v0.15.1

## Timeline

- 2026-08-10: disclosed

## References

- [https://github.com/fastschema/fastschema](https://github.com/fastschema/fastschema)
- [https://github.com/fastschema/fastschema/blob/main/pkg/auth/local.go](https://github.com/fastschema/fastschema/blob/main/pkg/auth/local.go)

## Related threats

- [fastschema stored XSS in SVG file upload](https://junglewise.ai/threats/cve-2026-72583-fastschema-stored-xss-in-svg-file-upload)
- [fastschema NULL pointer dereference in password recovery](https://junglewise.ai/threats/cve-2026-72582-fastschema-null-pointer-dereference-in-password-recovery)