{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-55087",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-06-16T14:41:54.578Z",
        "datePublished": "2026-08-19T19:29:16.221Z",
        "dateUpdated": "2026-08-19T19:29:16.221Z"
    },
    "containers": {
        "cna": {
            "title": "Etherpad: x-proxy-path header reflected into admin HTML/JS/CSS (cache-poisoning XSS) and concatenated into redirect (open-redirect)",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-79",
                            "lang": "en",
                            "description": "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')",
                            "type": "CWE"
                        }
                    ]
                },
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-444",
                            "lang": "en",
                            "description": "CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')",
                            "type": "CWE"
                        }
                    ]
                },
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-601",
                            "lang": "en",
                            "description": "CWE-601: URL Redirection to Untrusted Site ('Open Redirect')",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "NONE",
                        "baseScore": 6.1,
                        "baseSeverity": "MEDIUM",
                        "confidentialityImpact": "LOW",
                        "integrityImpact": "LOW",
                        "privilegesRequired": "NONE",
                        "scope": "CHANGED",
                        "userInteraction": "REQUIRED",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/ether/etherpad/security/advisories/GHSA-fjgc-3mj7-8rg8",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/ether/etherpad/security/advisories/GHSA-fjgc-3mj7-8rg8"
                },
                {
                    "name": "https://github.com/ether/etherpad/pull/7784",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/ether/etherpad/pull/7784"
                },
                {
                    "name": "https://github.com/ether/etherpad/commit/8c6104c5d5daf41f0d454acc04d42dffa0e0d996",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/ether/etherpad/commit/8c6104c5d5daf41f0d454acc04d42dffa0e0d996"
                },
                {
                    "name": "https://github.com/ether/etherpad/tree/3.1.0",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/ether/etherpad/tree/3.1.0"
                }
            ],
            "affected": [
                {
                    "vendor": "ether",
                    "product": "etherpad",
                    "versions": [
                        {
                            "version": ">= 2.1.0, < 3.1.0",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-08-19T19:29:16.221Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Etherpad is a real-time collaborative editor. From 2.1.0 until 3.1.0, Etherpad uses the attacker-controlled x-proxy-path request header in src/node/hooks/express/admin.ts when substituting paths into HTML, JavaScript, and CSS under /admin without sanitization, Vary: x-proxy-path, or Cache-Control: private, no-store. A shared proxy or CDN can cache the resulting response and serve attacker-injected script to an administrator. In src/node/hooks/express/specialpages.ts, version 3.0.0 also accepts a protocol-relative x-proxy-path value when constructing the /p/:pad/timeslider redirect, allowing redirection to an attacker-controlled host. The issues are exploitable when the deployment permits client-supplied x-proxy-path headers to reach Etherpad. This issue is fixed in version 3.1.0."
                }
            ],
            "source": {
                "advisory": "GHSA-fjgc-3mj7-8rg8",
                "discovery": "UNKNOWN"
            }
        }
    }
}