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A GitHub-reviewed security advisory, not necessarily under active exploitation the way our CISA KEV advisories are, but a real, disclosed vulnerability in an open-source dependency.
Affected packages
Vulnerable: >= 0.0.0-20260217145239-1cbfae0296f1, < 0.0.0-20260328015550-8d35e1eb5dd6
Patched in 0.0.0-20260328015550-8d35e1eb5dd6
Details
Any user that has enabled the OTP 2FA can have their TOTP reused during the standard 30 second validity window.
The https://github.com/pquerna/otp package doesn't include checking for already used TOTPs within its the validity window. This requires each application that uses the package to implement their own method of tracking and verifying that codes can't be reused.
Section 6.5.1 within the Authentication section of the OWASP ASVS recommends multiple checks, some of which involving TOTPs:
Verify that lookup secrets, out-of-band authentication requests or codes, and time-based one-time passwords (TOTPs) are only successfully usable once.
The OWASP WSTG also references this as one of their checks to look for:
Can the OTPs be used more than once?
https://github.com/user-attachments/assets/86a43374-39bf-4d61-8f6d-5cc440c99a1e
Any user who uses 2FA could be impacted if their traffic is able to be captured, they're phished/social engineered, or other methods of attack. This disrupts one layer of the defense-in-depth model surrounding 2FA.
Store a deny-list of TOTP codes for their validity windows and check submitted codes against it to ensure none are being reused. After their validity window has closed, the 2FA code can be removed from the list.
EPSS, exploit probability
Low0.38%
estimated chance of real-world exploitation in the next 30 days, higher than 32.2% of every CVE FIRST.org scores
Refreshed 11/6/2026, via FIRST.org's EPSS model, not CVSS, this measures likelihood of exploitation, not how severe it would be.
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A secure code review or supply chain review finds this before an advisory does.