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Vulnerability record · CVE-2026-87802 · published 14 September 2026

CVE-2026-87802: Improper verification of cryptographic signature vulnerability

Improper verification of cryptographic signature vulnerability in Apache Syncope. When SRA is configured for OAuth 2.0 without JWKS set URI assigned, an attacker can forge arbitrary JWTs to impersonate any user identity and permissions, gaining full access to services proxied by SRA. 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.

9.1 CVSS 3.1 Critical EPSS 0.28% · top 82.0% CWE-347 · Improper verification of cryptographic signature Deferred
9.1CVSS 3.1 base score
0.28%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
2References
14 Sep 2026Last modified by NVD

Description

Improper verification of cryptographic signature vulnerability in Apache Syncope. When SRA is configured for OAuth 2.0 without JWKS set URI assigned, an attacker can forge arbitrary JWTs to impersonate any user identity and permissions, gaining full access to services proxied by SRA. 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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References

LinkTags
https://lists.apache.org/thread/gx83cootj00kn8hqd73x1bp8441np33d
http://www.openwall.com/lists/oss-security/2026/09/14/25

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Source: NIST National Vulnerability Database (record CVE-2026-87802), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.