CVE-2024-39315

Pomerium exposed OAuth2 access and ID tokens in user info endpoint response

Workarounds

None

For more information

If you have any questions or comments about this advisory:

• Open an issue in pomerium/pomerium
• Email us at [email protected]

Credit to Vadim Sheydaev, aka Enr1g for reporting this issue.

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:

• the application verifies the Pomerium JWT for each request,
• the connection between Pomerium and the application is secured by mTLS,
• or the connection between Pomerium and the application is otherwise secured at the network layer.

CVE-2024-39315 has a CVSS score of 5.7 (Medium). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.26.1); upgrading removes the vulnerable code path.

Kodem intelligence

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Patched in Pomerium v0.26.1.

1. What is CVE-2024-39315? CVE-2024-39315 is a medium-severity security vulnerability in github.com/pomerium/pomerium (go), affecting versions < 0.26.1. It is fixed in 0.26.1.
2. How severe is CVE-2024-39315? CVE-2024-39315 has a CVSS score of 5.7 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/pomerium/pomerium are affected by CVE-2024-39315? github.com/pomerium/pomerium (go) versions < 0.26.1 is affected.
4. Is there a fix for CVE-2024-39315? Yes. CVE-2024-39315 is fixed in 0.26.1. Upgrade to this version or later.
5. Is CVE-2024-39315 exploitable, and should I be worried? Whether CVE-2024-39315 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2024-39315 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2024-39315? Upgrade github.com/pomerium/pomerium to 0.26.1 or later.

Other vulnerabilities in github.com/pomerium/pomerium