CVE-2026-34454 is a low-severity (CVSS 3.5) CWE-384 vulnerability in github.com/oauth2-proxy/oauth2-proxy/v7. A fix is available for github.com/oauth2-proxy/oauth2-proxy/v7 — see the affected versions and patch details below.
OAuth2 Proxy: Session cookie not cleared when rendering sign-in page
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 CVE-2026-34454.
EPSS Exploitation Probability
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
github.com/oauth2-proxy/oauth2-proxy/v7Real-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
A regression introduced in v7.11.0 is preventing OAuth2 Proxy from clearing the session cookie when rendering the sign-in page.
This only impacts deployments that rely on the sign-in page as part of their logout flow. In those setups, a user may be shown the sign-in page while the existing session cookie remains valid, so the browser session is not actually logged out. On shared workstations be it browsers or devices, a subsequent user could continue to use the previous user's authenticated session.
Deployments that use a dedicated logout/sign-out endpoint to terminate sessions are not affected.
Patches
This issue is fixed in v7.15.2.
Workarounds
Do not rely on the sign-in page to clear an existing session. Instead:
- Use the dedicated logout/sign-out endpoint of OAuth2 Proxy
- Ensure your application logout flow explicitly clears the OAuth2 Proxy session cookie before redirecting users to the sign-in page
- If needed, clear the session cookie at the reverse proxy or application layer as a temporary mitigation
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/oauth2-proxy/oauth2-proxy/v7 | ≥ 7.11.0&&< 7.15.2 | 7.15.2go get github.com/oauth2-proxy/oauth2-proxy/v7@v7.15.2 |
Affected Products
oauth2 proxyoauth2_proxy_projectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/oauth2-proxy/oauth2-proxy/v7, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/oauth2-proxy/oauth2-proxy/v7 to 7.15.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34454 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2026-34454 in your dependencies?
Find it across Go, including transitive dependencies.