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MEDIUM severity

Pomerium exposed OAuth2 access and ID tokens in user info endpoint responseGHSA-rrqr-7w59-637v

MEDIUMFix: pomerium/pomerium@4c7c432

GHSA-rrqr-7w59-637v is a medium-severity (CVSS 5.7) CWE-201 vulnerability in github.com/pomerium/pomerium. A fix is available for github.com/pomerium/pomerium — see the affected versions and patch details below.

Also known asCVE-2024-39315GO-2024-2965
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-rrqr-7w59-637v.

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs36th percentile — riskier than 36% of all scored CVEsHighest risk
0.00%0.31%0.62%0.93%0.4%0.4%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🐹github.com/pomerium/pomerium

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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.

Patches

Patched in Pomerium v0.26.1.

Workarounds

None

For more information

If you have any questions or comments about this advisory:

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

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/pomerium/pomeriumall versions0.26.1go get github.com/pomerium/pomerium@v0.26.1

Affected Products

1 product · 1 configurations
Application
pomeriumpomerium
< 0.26.1
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/pomerium/pomerium, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update github.com/pomerium/pomerium to 0.26.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rrqr-7w59-637v is resolved across your whole dependency graph.

  3. Workarounds

    Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

### Impact 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
O3 Security · Impact-Aware SCA

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