Description
smart-sso through 2.1.1 contains an open redirect vulnerability in the /login handler that allows unauthenticated attackers to steal OAuth2 authorization codes by supplying an unvalidated redirectUri parameter. Attackers can send crafted /login links to users with active SSO sessions, then redeem stolen codes at /oauth2/access_token with any valid client credentials to obtain victims' access tokens.
References7
- github.com/a466350665/smart-sso
- github.com/a466350665/smart-sso/blob/1.6.0/smart-sso-server/src…
- github.com/a466350665/smart-sso/blob/1.6.0/smart-sso-server/src…
- github.com/a466350665/smart-sso/blob/2.1.1/smart-sso-server/src…
- hackmd.io/@hieuPenguinnn/smart-sso-oauth2-code-leak-open-redire…
- www.vulncheck.com/advisories/smart-sso-through-2.1.1-oauth2-aut…
- hackmd.io/@hieuPenguinnn/smart-sso-oauth2-code-leak-open-redire…
Metrics
- CVSS 3.1
-
6.8
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N - CVSS 4.0
-
7.6
HIGH
Score source: CNA
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 37 · as of 10 November 2026
- CWE
- CWE-601
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.