High

SpringBlade 2.7.3 < 5.0.0 Privilege Escalation via Exposed Feign Endpoint

Type: advisorySources: OSV

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.

Products: Not specified
Affected versions: Not specified
Fixed versions: Not specified
CVEs: CVE-2026-56100
Confirmed fixed CVEs: Not specified
Updated in this feed: 3 Nov 2026, 09:54 UTC · Revision 1

Source evidence

SpringBlade 2.7.3 < 5.0.0 Privilege Escalation via Exposed Feign Endpoint

core-osv · Original source

Published 28 Aug 2026, 18:00 UTC

osv:CVE-2026-56100

Complete source record

{
  "id": "da8fb94ef26f0c50acddac0b55c7b0e23f2d6a2eae65e91abe4c41650aaa21f0",
  "url": "https://osv.dev/vulnerability/CVE-2026-56100",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "SpringBlade 2.7.3 < 5.0.0 Privilege Escalation via Exposed Feign Endpoint",
    "summary": "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.",
    "evidence": "osv:CVE-2026-56100",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-56100",
      "aliases": [
        "CVE-2026-56100"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/chillzhuang/springblade",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "079fc00e44f582f866a0ec6fd26d87417b742044"
                },
                {
                  "fixed": "c69b9547c942c697da2f3ee6a9265b6004abd645"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "2.7.3"
                      },
                      {
                        "fixed": "5.0.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "c69b9547c942c697da2f3ee6a9265b6004abd645"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v4.10.0",
            "v4.9.0",
            "v4.8.0",
            "v4.7.0",
            "v4.6.0",
            "v4.5.0",
            "v4.4.0",
            "v4.3.0",
            "v4.2.0",
            "4.1.0",
            "v4.0.0",
            "v3.7.1",
            "v3.7.0",
            "v3.6.0",
            "v3.5.0",
            "v3.4.1",
            "v3.4.0",
            "v3.3.1",
            "v3.3.0",
            "v3.2.0",
            "v3.1.0",
            "v3.03",
            "v3.0.2",
            "v3.0.1",
            "v3.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-56100.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:27.797345297Z",
      "provider": "osv",
      "references": [
        "https://gitee.com/smallc/SpringBlade",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56100.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-56100",
        "https://www.vulncheck.com/advisories/springblade-privilege-escalation-via-exposed-feign-endpoint",
        "https://github.com/chillzhuang/SpringBlade/commit/c69b9547c942c697da2f3ee6a9265b6004abd645",
        "https://github.com/chillzhuang/SpringBlade",
        "https://github.com/chillzhuang/SpringBlade/releases#release-v5.0.0",
        "https://gist.github.com/sud0why/e73405057dd7414a8c221ef17e0d0059#file-cve-2026-56100-springblade-authbypass-en-md"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-862"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56100.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-56100",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 494329,
  "published_at": "2026-08-28T18:00:36.953+00:00"
}