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
2026-08-19T19:29:16Z
Modified
2026-10-28T02:30:41Z
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
fa1c6b2e43d0510c851643cb7ba67cf042331a37
Fixed
8c6104c5d5daf41f0d454acc04d42dffa0e0d996
Database specific
Show details 
{
    "extracted_events":  [
        {
            "range":  [
                {
                    "introduced":  "2.1.0"
                },
                {
                    "fixed":  "3.1.0"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StringRangeExpression"
        },
        {
            "range":  [
                {
                    "fixed":  "8c6104c5d5daf41f0d454acc04d42dffa0e0d996"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        }
    ]
}

Affected versions

2.*
2.1.0
2.1.1
2.2.0
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
2.2.6
2.2.7
2.3.0
2.3.1
2.3.2
2.4.0
2.4.1
2.4.2
2.5.0
2.5.1
2.5.3
2.6.0
2.6.1
2.7.0
2.7.1
2.7.2
2.7.3
3.*
3.0.0
v2.*
v2.1.0
v2.1.1
v2.2.0
v2.2.1
v2.2.2
v2.2.3
v2.2.4
v2.2.5
v2.2.6
v2.2.7
v2.3.0
v2.3.1
v2.3.2
v2.4.0
v2.4.1
v2.4.2
v2.5.0
v2.5.1
v2.5.3
v2.6.0
v2.6.1
v2.7.0
v2.7.1
v2.7.2
v2.7.3
v3.*
v3.0.0

Database specific

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