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CVE-2026-87785
Apache Syncope: JWT subject spoofing
Overview
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.

Details
INFO

Published Date :

Sept. 14, 2026, 11:17 a.m.

Last Modified :

Sept. 14, 2026, 11:17 a.m.

Remotely Exploit :

No

Source :

[email protected]
Impact
Affected Products

The following products are affected by CVE-2026-87785 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Apache syncope
: Total Affected Vendor : 1 | Products : 1
Solution
Upgrade Apache Syncope to patched versions to fix authentication bypass via JWKS disclosure.
  • Upgrade to Apache Syncope version 4.0.8 or later.
  • Upgrade to Apache Syncope version 4.1.3 or later.
  • Secure JWKS endpoint and restrict access.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-87785.

URL Resource
https://lists.apache.org/thread/3t3om8mny7ng52q053pdzpmtdtosnqoo
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-87785 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-87785 weaknesses.

CAPEC-21: Exploitation of Trusted Identifiers Exploitation of Trusted Identifiers CAPEC-22: Exploiting Trust in Client Exploiting Trust in Client CAPEC-59: Session Credential Falsification through Prediction Session Credential Falsification through Prediction CAPEC-60: Reusing Session IDs (aka Session Replay) Reusing Session IDs (aka Session Replay) CAPEC-94: Adversary in the Middle (AiTM) Adversary in the Middle (AiTM) CAPEC-459: Creating a Rogue Certification Authority Certificate Creating a Rogue Certification Authority Certificate CAPEC-461: Web Services API Signature Forgery Leveraging Hash Function Extension Weakness Web Services API Signature Forgery Leveraging Hash Function Extension Weakness CAPEC-473: Signature Spoof Signature Spoof CAPEC-476: Signature Spoofing by Misrepresentation Signature Spoofing by Misrepresentation CAPEC-667: Bluetooth Impersonation AttackS (BIAS) Bluetooth Impersonation AttackS (BIAS)

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-87785 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-87785 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Sep. 14, 2026

    Action Type Old Value New Value
    Added 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.
    Added CWE CWE-290
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/87xxx/CVE-2026-87785.json">CVE-2026-87785</a>
    Added Reference https://lists.apache.org/thread/3t3om8mny7ng52q053pdzpmtdtosnqoo
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
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