CVE-2026-55089Public exploitNetwork attack vector

Admin API access via admin-claim presence check

Published Aug 19, 2026 · Updated Aug 19, 2026

Incorrect authorization in Etherpad before 3.1.0 allows remote authenticated users to read, modify, or delete pads via OAuth API calls. In src/node/handler/APIHandler.ts, the authorization_code path uses jose requiredClaims with admin, which verifies only that the claim exists; src/node/security/OAuth2Provider.ts issues admin:false for configured non-admin users, so any valid signed token with that claim passes the gate. Exposure requires the JWT-based OAuth path rather than apikey mode and a non-admin account that can complete the embedded OIDC flow, allowing instance-wide pad enumeration, content changes, revision rollback, or pad deletion.

CVSS severity9.9
Critical
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Etherpad before 3.1.0 allows remote authenticated users to read, modify, or delete pads via OAuth API calls. In src/node/handler/APIHandler.ts, the authorization_code path uses jose requiredClaims with admin, which verifies only that the claim exists; src/node/security/OAuth2Provider.ts issues admin:false for configured non-admin users, so any valid signed token with that claim passes the gate. Exposure requires the JWT-based OAuth path rather than apikey mode and a non-admin account that can complete the embedded OIDC flow, allowing instance-wide pad enumeration, content changes, revision rollback, or pad deletion.

The record

CVE
CVE-2026-55089
Published
Aug 19, 2026
Updated
Aug 19, 2026
Vendor
Etherpad Foundation
Product
Etherpad
Classifications
CWE-863, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 2.1.0, < 3.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Etherpad Foundation · Etherpadversion=>= 2.1.0, < 3.1.0

Published CVSS scores

9.9GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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