CVE-2024-39315

Pomerium is an identity and context-aware access proxy. Prior to version 0.26.1, the Pomerium user info page (at /.pomerium) unintentionally included serialized OAuth2 access and ID tokens from the logged-in user's session. These tokens are not intended to be exposed to end users. This issue may be more severe in the presence of a cross-site scripting vulnerability in an upstream application proxied through Pomerium. If an attacker could insert a malicious script onto a web page proxied through Pomerium, that script could access these tokens by making a request to the /.pomerium endpoint. Upstream applications that authenticate only the ID token may be vulnerable to user impersonation using a token obtained in this manner. Note that an OAuth2 access token or ID token by itself is not sufficient to hijack a user's Pomerium session. Upstream applications should not be vulnerable to user impersonation via these tokens provided the application verifies the Pomerium JWT for each request