CVE-2024-27918High· 8.2▾ TwilightCoder's OIDC authentication allows email with partially matching domain to register
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 45.1 · likelihood 0.2 · exploitation 0
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Exploit-prediction probability, daily snapshots since Sep 12.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
1.0%
A vulnerability in Coder's OIDC authentication could allow an attacker to bypass the CODER_OIDC_EMAIL_DOMAIN verification and create an account with an email not in the allowlist. Deployments are only affected if the OIDC provider allows users to create accounts on the provider (such as public providers like google.com).
During OIDC registration, the user's email was improperly validated against the allowed CODER_OIDC_EMAIL_DOMAINs. This could allow a user with a domain that only partially matched an allowed domain to successfully login or register (e.g. [email protected] would match the allowed domain corp.com).
An attacker could register a domain name that exploited this vulnerability and register on a Coder instance with a public OIDC provider.
Coder instances with OIDC enabled and protected by the CODER_OIDC_EMAIL_DOMAIN configuration.
Coder instances using a private OIDC provider are not affected, as arbitrary users cannot register through a private OIDC provider without first having an account on the provider.
Public OIDC providers (such as google.com without permitted domains set on the OAuth2 App) are impacted.
GitHub authentication and external authentication are not impacted.
To check if your deployment was exploited:
action:register filter)@exploitcorp.com instead of @corp.com)This vulnerability is remedied in
All versions prior to these patches are affected by the vulnerability. It is recommended that customers upgrade their deployments as soon as possible if they are utilizing OIDC authentication with the CODER_OIDC_EMAIL_DOMAIN setting.
https://github.com/coder/coder/security/advisories/GHSA-7cc2-r658-7xpf https://github.com/coder/coder/commit/4439a920e454a82565e445e4376c669e3b89591c https://nvd.nist.gov/vuln/detail/CVE-2024-27918
github.com/coder/coder/v2 >= 2.8.0, < 2.8.4github.com/coder/coder/v2 >= 2.7.0, < 2.7.3github.com/coder/coder/v2 < 2.6.1github.com/coder/coder <= 0.27.3Upgrade to a patched release:
github.com/coder/coder/v2 2.8.4github.com/coder/coder/v2 2.7.3github.com/coder/coder/v2 2.6.1Connected by shared product, vendor, weakness, or advisory.
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