Description
ZKEACMS through 4.4 contains an authentication bypass vulnerability that allows unauthenticated attackers to forge REST API JWT bearer tokens using a hard-coded HMAC-SHA256 signing key in JwtBearerDefaults.cs. Attackers can sign a token with the Name claim set to 'admin' to call ApiAuthorize endpoints, modifying articles and products and reading form submissions.
References7
- github.com/SeriaWei/ZKEACMS/blob/v4.4/src/ZKEACMS/Api/JwtBearer…
- github.com/SeriaWei/ZKEACMS/blob/v4.4/src/ZKEACMS/BuilderAuthen…
- github.com/SeriaWei/ZKEACMS/issues/531
- hackmd.io/@hieuPenguinnn/zkeacms-hardcoded-jwt-signing-key-admi…
- www.vulncheck.com/advisories/zkeacms-through-4.4-authentication…
- github.com/SeriaWei/ZKEACMS/issues/531
- hackmd.io/@hieuPenguinnn/zkeacms-hardcoded-jwt-signing-key-admi…
Metrics
- CVSS 3.1
-
8.6
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L - CVSS 4.0
-
8.8
HIGH
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:L/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: 39 · as of 10 November 2026
- CWE
- CWE-321
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.