CVE-2023-49208: scheme/webauthn.c in Glewlwyd SSO server before 2.7.6 has a possible buffer overflow during FIDO2 credentials

Q: How do I fix CVE-2023-49208?

glewlwyd sso server: upgrade to 2.7.6. Exact commands for each OS are on this page.

Q: Is CVE-2023-49208 being exploited?

CVE-2023-49208 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-49208 affect?

CVE-2023-49208 affects glewlwyd sso server. Severity is critical (CVSS 9.8). scheme/webauthn.c in Glewlwyd SSO server before 2.7.6 has a possible buffer overflow during FIDO2 credentials validation in webauthn registration.

Q: How urgent is CVE-2023-49208?

Priority 54/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.8REMOTEUPGRADE

CVE-2023-49208 is a critical-severity flaw (CVSS 9.8) affecting glewlwyd sso server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

scheme/webauthn.c in Glewlwyd SSO server before 2.7.6 has a possible buffer overflow during FIDO2 credentials validation in webauthn registration.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.9% (top 41%)
CISA exploited list	No
Weakness	CWE-120
Published	2023-11-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: glewlwyd sso server project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-11-23 18:15 UTCPublished CVE record published
2026-06-17 06:35 UTCUpdated Record last modified

glewlwyd sso server project glewlwyd sso server UPGRADE

Affected: < 2.7.6

Fixed in: 2.7.6

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy glewlwyd-sso-server || rpm -q glewlwyd-sso-server || glewlwyd-sso-server --version

2. UPGRADE to 2.7.6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade glewlwyd-sso-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade glewlwyd-sso-server

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-49208?

glewlwyd sso server: upgrade to 2.7.6. Exact commands for each OS are on this page.

Is CVE-2023-49208 being exploited?

CVE-2023-49208 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-49208 affect?

CVE-2023-49208 affects glewlwyd sso server. Severity is critical (CVSS 9.8). scheme/webauthn.c in Glewlwyd SSO server before 2.7.6 has a possible buffer overflow during FIDO2 credentials validation in webauthn registration.

How urgent is CVE-2023-49208?

Priority 54/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2024-25715 MEDIUM 6.1 UPGRADE Glewlwyd SSO server 2.x through 2.7.6 allows open redirection via redirect_uri.

References

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