CVE-2026-34454
LOWCVE-2026-34454 is a low-severity (CVSS 3.5) vulnerability in github.com/oauth2-proxy/oauth2-proxy/v7. O3 Security confirms whether CVE-2026-34454 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
OAuth2 Proxy: Session cookie not cleared when rendering sign-in page
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
OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. A regression introduced in 7.11.0 prevents OAuth2 Proxy from clearing the session cookie when rendering the sign-in page. In deployments that rely on the sign-in page as part of their logout flow, a user may be shown the sign-in page while the existing session cookie remains valid, meaning the browser session is not actually logged out. On shared workstations 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. This issue is fixed in 7.15.2
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/oauth2-proxy/oauth2-proxy/v7 | ≥ 7.11.0&&< 7.15.2 | 7.15.2 |
Detection & 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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-34454 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-34454. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-34454 in your dependencies?
O3 detects CVE-2026-34454 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.