Summary
nginx ignition has TOTP Reuse During Validity Window
Any user that has enabled the OTP 2FA can have their TOTP reused during the standard 30 second validity window.
Details
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?
PoC
https://github.com/user-attachments/assets/86a43374-39bf-4d61-8f6d-5cc440c99a1e
Similar CVEs
Impact
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.
The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.
CVE-2026-61630 has a CVSS score of 4.2 (Medium). The vector is network-reachable, high privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.0.0-20260328015550-8d35e1eb5dd6); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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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.
Frequently Asked Questions
- What is CVE-2026-61630? CVE-2026-61630 is a medium-severity improper authentication vulnerability in github.com/lucasdillmann/nginx-ignition (go), affecting versions >= 0.0.0-20260217145239-1cbfae0296f1, < 0.0.0-20260328015550-8d35e1eb5dd6. It is fixed in 0.0.0-20260328015550-8d35e1eb5dd6. The application does not adequately verify the identity of a user, device, or process before granting access.
- How severe is CVE-2026-61630? CVE-2026-61630 has a CVSS score of 4.2 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/lucasdillmann/nginx-ignition are affected by CVE-2026-61630? github.com/lucasdillmann/nginx-ignition (go) versions >= 0.0.0-20260217145239-1cbfae0296f1, < 0.0.0-20260328015550-8d35e1eb5dd6 is affected.
- Is there a fix for CVE-2026-61630? Yes. CVE-2026-61630 is fixed in 0.0.0-20260328015550-8d35e1eb5dd6. Upgrade to this version or later.
- Is CVE-2026-61630 exploitable, and should I be worried? Whether CVE-2026-61630 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-61630 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-61630? Upgrade
github.com/lucasdillmann/nginx-ignitionto 0.0.0-20260328015550-8d35e1eb5dd6 or later.