CVE-2026-87785

EUVD-2026-77368
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
apacheCNA
9.1 CRITICAL
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
apachesyncope
𝑥
≤ 3.0.16
CNA
apachesyncope
𝑥
≤ 4.0.7
CNA
apachesyncope
𝑥
≤ 4.1.2
CNA
Common Weakness Enumeration
References
https://lists.apache.org/thread/3t3om8mny7ng52q053pdzpmtdtosnqoo
http://www.openwall.com/lists/oss-security/2026/09/14/24