CVE-2026-87785

Critical

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.

SeverityCritical

CVSS9.1

Exploit probability—

ProductApache Syncope

PublishedSep 14, 2026

First seenSep 14, 2026

Weakness typeCWE-290CWE-290

How to fix

Vendor advisories

lists.apache.org/thread/3t3om8mny7ng52q053pdzpmtdtosnqoo

Affected products

Product	Affected versions	Fixed in
Apache Software Foundation Apache Syncope	3.0.0-M0 ≤ v ≤ 3.0.16, 4.0.0-M0 ≤ v ≤ 4.0.7, 4.1.0-M0 ≤ v ≤ 4.1.2	—

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