CVE-2026-55087

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Source
https://cve.org/CVERecord?id=CVE-2026-55087
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55087.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-55087
Aliases
Published
2026-08-19T19:29:16.221Z
Modified
2026-08-21T03:46:29.676319840Z
Severity
  • 6.1 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N CVSS Calculator
Summary
Etherpad: x-proxy-path header reflected into admin HTML/JS/CSS (cache-poisoning XSS) and concatenated into redirect (open-redirect)
Details

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.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-444",
        "CWE-601",
        "CWE-79"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55087.json"
}
References

Affected packages

Git / github.com/ether/etherpad

Affected ranges

Type
GIT
Repo
https://github.com/ether/etherpad
Events
Introduced
c45b7a361e56e6c753cd1c9b8cc4e1017090ce9c
Fixed
8c6104c5d5daf41f0d454acc04d42dffa0e0d996
Database specific
Show details 
{
    "extracted_events": [
        {
            "introduced": "2.1.0"
        },
        {
            "fixed": "3.1.0"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ]
}

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55087.json"