by Kastro
Paper/Archive/CVE-2026-87785

CVE-2026-87785

Apache Software Foundation Apache Syncope — Apache Syncope: JWT subject spoofing

EPSS 0.5%CVSS 9.1
critical.is priorityof 100
37
CVSS 9.1 (ADP)9.1 / 10 × 3027.3Not in CISA KEV+300.0EPSS percentile 46.0.460 × 209.2No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Apache Syncope3.0.0-M0 – 3.0.16–CNA
Apache Syncope4.0.0-M0 – 4.0.7–CNA
Apache Syncope4.1.0-M0 – 4.1.2–CNA

Scores by source

CISA ADP9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

advisorylists.apache.org/thread/3t3om8mny7ng52q053pdzpmtdtosnqoorefopenwall.com/lists/oss-security/2026/09/14/24