CVE-2026-28513
HIGHCVE-2026-28513 is a high-severity (CVSS 8.5) CWE-863 vulnerability in github.com/pocket-id/pocket-id/backend. O3 Security confirms whether CVE-2026-28513 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Pocket ID: OIDC authorization code validation uses AND instead of OR, allowing cross-client token exchange
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-28513.
Real-World Exposure
github.com/pocket-id/pocket-id/backendReal-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
Pocket ID is an OIDC provider that allows users to authenticate with their passkeys to your services. Prior to 2.4.0, the OIDC token endpoint rejects an authorization code only when both the client ID is wrong and the code is expired. This allows cross-client code exchange and expired code reuse. This vulnerability is fixed in 2.4.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/pocket-id/pocket-id/backend | all versions | 0.0.0-20260307173642-b59e35cb59ae |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/pocket-id/pocket-id/backend. 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/pocket-id/pocket-id/backend to 0.0.0-20260307173642-b59e35cb59ae or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28513 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-2026-28513 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-2026-28513. 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-2026-28513 in your dependencies?
O3 detects CVE-2026-28513 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.