CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
AI Score
Confidence
High
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 an XSS 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:
Patched in Pomerium v0.26.1.
None
If you have any questions or comments about this advisory:
Credit to Vadim Sheydaev, aka Enr1g for reporting this issue.