CVE-2026-87785

Apache Syncope: JWT subject spoofing

Published Sep 14, 2026 CVSS 3.1 · 9.1 Critical EPSS < 1% KEV · Not listed
Description
Authentication bypass by spoofing vulnerability in Apache Syncope.



When the configured JWKS settings for internal JWT authentication are disclosed (at least protocol and key), an attacker can spoof another user's privileges after completing a successful authentication and obtaining a valid JWT.

This issue affects Apache Syncope: from 3.0.0-M0 through 3.0.16, from 4.0.0-M0 through 4.0.7, from 4.1.0-M0 through 4.1.2.



Users are recommended to upgrade to version 4.0.8 / 4.1.3, which fix this issue.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Apache
Apache syncope
Vendors & Products Apache
Apache syncope
Type Values Removed Values Added
References
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Authentication bypass by spoofing vulnerability in Apache Syncope. When the configured JWKS settings for internal JWT authentication are disclosed (at least protocol and key), an attacker can spoof another user's privileges after completing a successful authentication and obtaining a valid JWT. This issue affects Apache Syncope: from 3.0.0-M0 through 3.0.16, from 4.0.0-M0 through 4.0.7, from 4.1.0-M0 through 4.1.2. Users are recommended to upgrade to version 4.0.8 / 4.1.3, which fix this issue.
Title Apache Syncope: JWT subject spoofing
Weaknesses CWE-290
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
apache
Published
Updated
Sep 14, 2026, 7:45 PM
Reserved
Sep 9, 2026, 9:19 AM
Status
Deferred
Published
Sep 14, 2026, 11:17 AM
Modified
Sep 14, 2026, 8:58 PM