CVE-2026-56100
SpringBlade versions from 2.7.3 up to but not including 5.0.0 contain a privilege escalation vulnerability that allows authenticated attackers to create system administrator accounts by sending crafted POST requests to an unprotected internal Feign…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.29%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
SpringBlade versions from 2.7.3 up to but not including 5.0.0 contain a privilege escalation vulnerability that allows authenticated attackers to create system administrator accounts by sending crafted POST requests to an unprotected internal Feign user-creation endpoint exposed via @RestController without authorization checks. Attackers can exploit the gateway's authentication filter, which only validates JWT parsing without verifying user roles or caller identity, and leverage a hardcoded JWT signing key embedded in publicly available JARs to forge tokens and escalate privileges from a low-privilege user to administrator, enabling cross-tenant data pollution and persistent backdoor access.
- CVSS 4.0
- 8.6 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/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/M
- EPSS
- 0.29% probability · 21th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-862
- Source
- disclosure@vulncheck.com
References
- https://gist.github.com/sud0why/e73405057dd7414a8c221ef17e0d0059#file-cve-2026-56100-springblade-authbypass-en-md
- https://github.com/chillzhuang/SpringBlade
- https://github.com/chillzhuang/SpringBlade/commit/c69b9547c942c697da2f3ee6a9265b6004abd645
- https://github.com/chillzhuang/SpringBlade/releases#release-v5.0.0
- https://www.vulncheck.com/advisories/springblade-privilege-escalation-via-exposed-feign-endpoint
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.