CVE-2026-116672: Kaskade · Authlib RFC 7592 examples omit registration-access-token client binding
Affects kaskadeSource GCVE Database
Not known to be exploited · CVSS 8.8 High.
Data as of 31 Oct 2026, 16:07 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 8.8 |
|---|
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 27 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewkaskadepkg:brew/kaskadeOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should avoid deploying the vulnerable example code as-is. Developers must implement the authenticate_client and check_permission methods to explicitly verify that the registration_access_token presented is bound to the client being accessed, ensuring the token's client identity matches the target client_id. Until a fixed version or official guidance is released, careful custom implementation of these checks is required to prevent authorization bypass.
Description
The Kaskade OAuth 2.0 Dynamic Client Registration Management implementation in Authlib has a security flaw where example code omits the critical check binding the registration_access_token to the specific client. This omission allows an attacker possessing any valid registration_access_token and knowledge of a client_id to bypass authorization and access, modify, or delete that client's registration. The vulnerability affects versions 4.0.4 and later. The CVSS 3.1 score is 8.8 (high severity).
References
- github.com/authlib/authlib/security/advisories/GHSA-c73q-w75p-j82v (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-116672 (opens in a new tab)
- github.com/authlib/authlib/commit/1bd2a313492ce0a4d0571c150730907aa3fc91ff (opens in a new tab)
- github.com/authlib/authlib (opens in a new tab)
- github.com/authlib/authlib/releases/tag/v1.9.1 (opens in a new tab)