Quick answers
- Is CVE-2026-51584 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-51584 being exploited in the wild.
- How severe is CVE-2026-51584?
- Critical severity, with a CVSS score of 9.8, published 11 August 2026.
- Which products and versions are affected?
- Usememos Memos ≤ v0.27.1.
- Is there a fix for CVE-2026-51584?
- A patch was published on 2026-04-23: Fixed in v0.28.0 via commit d688914b Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-51584 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-51584?
- Check whether you run Usememos Memos at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is an authentication bypass (CWE-287 / CWE-284) in the SSO sign-in handler (server/router/api/v1/auth_service.go). When SSO is enabled, the application resolves local user accounts using only the identity provider's identifier (e.g., username, email, preferred_username) as a lookup key, without binding to the IdP's stable subject claim (sub). An unauthenticated remote attacker can exploit this by setting their identifier on any configured public IdP to match a victim's Memos username, completing the OAuth2 authorization flow, and receiving a valid session token for the victim's account. The attack requires knowledge of a target username and a configured public IdP, but no prior access. The vulnerability was patched in v0.28.0 by introducing a user_identity table that binds external identities to local users via stable subject claims.
Affected products
- usememos Memos ≤ v0.27.1
Timeline
- 2026-08-11: disclosed: Advisory published on NVD
- 2026-04-23: patched: Fixed in v0.28.0 via commit d688914b