CVE-2026-87802
Deferred Deferred - Pending Action

JWT Forgery in Apache Syncope via Missing JWKS URI

Publication date: 2026-09-14

Last updated on: 2026-09-14

Assigner: Apache Software Foundation

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.

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Meta Information

Published
2026-09-14
Last Modified
2026-09-14
Generated
2026-09-15
AI Q&A
2026-09-14
EPSS Evaluated
N/A
NVD
CVE-2026-87802
EUVD
EUVD-2026-77358

Affected Vendors & Products

Showing 5 associated CPEs
Vendor Product Version / Range
apache syncope From 3.0.0-M0 (inc) to 3.0.16 (inc)
apache syncope From 4.0.0-M0 (inc) to 4.0.7 (inc)
apache syncope From 4.1.0-M0 (inc) to 4.1.2 (inc)
apache syncope 4.0.8
apache syncope 4.1.3

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-347 The product does not verify, or incorrectly verifies, the cryptographic signature for data.

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Executive Summary

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

Detection Guidance

To detect this vulnerability, check if Apache Syncope is running versions between 3.0.0-M0 and 3.0.16, 4.0.0-M0 and 4.0.7, or 4.1.0-M0 and 4.1.2. Verify if SRA is configured for OAuth 2.0 without a JWKS set URI. Inspect JWT handling for improper signature verification.

Impact Analysis

An attacker could exploit this to impersonate any user, gaining unauthorized access to systems and data managed by Apache Syncope. This could lead to data breaches, unauthorized modifications, or complete system compromise depending on the user permissions.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating GDPR's data protection requirements and HIPAA's security and privacy rules. Organizations may face legal penalties, reputational damage, and loss of trust due to non-compliance.

Mitigation Strategies

Upgrade Apache Syncope to version 4.0.8 or 4.1.3 or later to fix the improper JWT verification issue.

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