CVE-2021-40818
CRITICALCVSS 9.8/10EPSS 1.43%
Last modified
CVE-2021-40818 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. scheme/webauthn.c in Glewlwyd SSO server through 2.5.3 has a buffer overflow during FIDO2 signature validation in webauthn registration.. EPSS estimates a 1.43% chance of exploitation in the next 30 days.
Description
scheme/webauthn.c in Glewlwyd SSO server through 2.5.3 has a buffer overflow during FIDO2 signature validation in webauthn registration.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Glewlwyd Sso Server Project | Glewlwyd Sso Server | <= 2.5.3 |
References
- https://bugs.debian.org/993867Issue Tracking, Mailing List, Third Party Advisory
- https://github.com/babelouest/glewlwyd/commit/0efd112bb62f566877750ad62ee828bff579b4e2Patch, Third Party Advisory
- https://bugs.debian.org/993867Issue Tracking, Mailing List, Third Party Advisory
- https://github.com/babelouest/glewlwyd/commit/0efd112bb62f566877750ad62ee828bff579b4e2Patch, Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-40818?
scheme/webauthn.c in Glewlwyd SSO server through 2.5.3 has a buffer overflow during FIDO2 signature validation in webauthn registration.
How severe is CVE-2021-40818?
CVE-2021-40818 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.43% probability of exploitation in the next 30 days.
How do I fix CVE-2021-40818?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2021-40818?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST