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Medium

Caddy vulnerable to cross-origin config application via local admin API /load (caddy)

Type: advisorySources: OSV

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, the local caddy admin API (default listen `127.0.0.1:2019`) exposes a state-changing `POST /load` endpoint that replaces the entire running configuration. When origin enforcement is not enabled (`enforce_origin` not configured), the admin endpoint accepts cross-origin requests (e.g., from attacker-controlled web content in a victim browser) and applies an attacker-supplied JSON config. This can change the admin listener settings and alter HTTP server behavior without user intent. Version 2.11.1 contains a fix for the issue.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-27589
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 01:59 UTC · Revision 1

Source evidence

Caddy vulnerable to cross-origin config application via local admin API /load (caddy)

core-osv · Original source

Published 24 Feb 2026, 16:30 UTC

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, the local caddy admin API (default listen `127.0.0.1:2019`) exposes a state-changing `POST /load` endpoint that replaces the entire running configuration. When origin enforcement is not enabled (`enforce_origin` not configured), the admin endpoint accepts cross-origin requests (e.g., from attacker-controlled web content in a victim browser) and applies an attacker-supplied JSON config. This can change the admin listener settings and alter HTTP server behavior without user intent. Version 2.11.1 contains a fix for the issue.

osv:CVE-2026-27589
Complete source record
{
  "id": "0e9b80304133468c472ca0ee63decfeb170bfae8447b400b801018842174d877",
  "url": "https://osv.dev/vulnerability/CVE-2026-27589",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Caddy vulnerable to cross-origin config application via local admin API /load (caddy)",
    "summary": "Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, the local caddy admin API (default listen `127.0.0.1:2019`) exposes a state-changing `POST /load` endpoint that replaces the entire running configuration. When origin enforcement is not enabled (`enforce_origin` not configured), the admin endpoint accepts cross-origin requests (e.g., from attacker-controlled web content in a victim browser) and applies an attacker-supplied JSON config. This can change the admin listener settings and alter HTTP server behavior without user intent. Version 2.11.1 contains a fix for the issue.",
    "evidence": "osv:CVE-2026-27589",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-27589",
      "aliases": [
        "CVE-2026-27589",
        "GHSA-879p-475x-rqh2",
        "GO-2026-4537"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/caddyserver/caddy",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "6610e2f1bd8f54853006eefd3849c9965190e57f"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.11.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "6610e2f1bd8f54853006eefd3849c9965190e57f"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v2.11.1"
                  },
                  {
                    "cpe": "cpe:2.3:a:caddyserver:caddy:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.11.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.11.0",
            "v2.11.0-beta.2",
            "v2.11.0-beta.1",
            "v2.10.2",
            "v2.10.1",
            "v2.10.0",
            "v2.10.0-beta.4",
            "v2.10.0-beta.3",
            "v2.9.1",
            "v2.10.0-beta.2",
            "v2.10.0-beta.1",
            "v2.9.0",
            "v2.9.0-beta.3",
            "v2.9.0-beta.2",
            "v2.9.0-beta.1",
            "v2.8.4",
            "v2.8.3",
            "v2.8.2",
            "v2.8.1",
            "v2.8.0",
            "v2.8.0-rc.1",
            "v2.8.0-beta.2",
            "v2.8.0-beta.1",
            "v2.7.5",
            "v2.7.4",
            "v2.7.3",
            "v2.7.2",
            "v2.7.1",
            "v2.7.0",
            "v2.7.0-beta.2",
            "v2.7.0-beta.1",
            "v2.6.4",
            "v2.6.3",
            "v2.6.2",
            "v2.6.1",
            "v2.6.0",
            "v2.6.0-beta.5",
            "v2.6.0-beta.4",
            "v2.6.0-beta.3",
            "v2.6.0-beta.2",
            "v2.6.0-beta.1",
            "v2.5.2",
            "v2.5.1",
            "v2.5.0",
            "v2.5.0-rc.1",
            "v2.5.0-beta.1",
            "v2.4.6",
            "v2.4.5",
            "v2.4.4",
            "v2.4.3",
            "v2.4.2",
            "v2.4.1",
            "v2.4.0",
            "v2.4.0-rc.1",
            "v2.4.0-beta.2",
            "v2.4.0-beta.1",
            "v2.3.0-rc.2",
            "v2.3.0",
            "v2.3.0-rc.1",
            "v2.3.0-beta.1",
            "v2.2.3",
            "v2.2.1",
            "v2.2.0",
            "v2.2.0-rc.3",
            "v2.2.0-rc.2",
            "v2.2.0-rc.1",
            "v2.1.1",
            "v2.1.0",
            "v2.1.0-beta.2",
            "v2.1.0-beta.1",
            "v2.0.0",
            "v2.0.0-rc.3",
            "v2.0.0-rc.2",
            "v2.0.0-rc.1",
            "v2.0.0-beta.20",
            "v2.0.0-beta.19",
            "v2.0.0-beta.18",
            "v2.0.0-beta.17",
            "v2.0.0-beta.16",
            "v2.0.0-beta.15",
            "v2.0.0-beta.14",
            "v2.0.0-beta.13",
            "v2.0.0-beta12",
            "v2.0.0-beta11",
            "v2.0.0-beta10",
            "v2.0.0-beta9",
            "v2.0.0-beta8",
            "v2.0.0-beta7",
            "v2.0.0-beta6",
            "v2.0.0-beta5",
            "v2.0.0-beta4",
            "v2.0.0-beta3",
            "v2.0.0-beta2",
            "v2.0.0-beta1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27589.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.438287694Z",
      "provider": "osv",
      "references": [
        "https://github.com/caddyserver/caddy/releases/tag/v2.11.1",
        "https://github.com/user-attachments/files/25079818/poc.zip",
        "https://github.com/user-attachments/files/25079820/PR_DESCRIPTION.md",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27589.json",
        "https://github.com/caddyserver/caddy/security/advisories/GHSA-879p-475x-rqh2",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-27589"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-352"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27589.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-27589",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 499520,
  "published_at": "2026-02-24T16:30:52.016+00:00"
}