Critical severity · published Sep 14, 2026
CVE-2026-87802
Apache Syncope: SRA OAuth2 JWT signature verification bypass
9.1
CVSS
0.3%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 20% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AS
Apache Syncope · Apache Software Foundation
3.0.0-M0 through 3.0.16; 4.0.0-M0 through 4.0.7; 4.1.0-M0 through 4.1.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-87802
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-87802
lists.apache.org
https://lists.apache.org/thread/gx83cootj00kn8hqd73x1bp8441np33d
www.openwall.com
http://www.openwall.com/lists/oss-security/2026/09/14/25
More from Apache Syncope
9.8
CVE-2026-73370
Apache Syncope: Cross-Realm boundaries reconciliation bypass
9.8
CVE-2026-73470
Apache Syncope: Delegating users can grant unowned Roles
9.8
CVE-2026-73579
Apache Syncope: Non-recursive Any search could skip Realms restrictions
9.8
CVE-2026-75030
Apache Syncope: Incomplete authorization checks for Group members deprovisioning
9.8
CVE-2026-77051
Apache Syncope: SQL injection via unsanitized entityKey and opEvent in Audit Events search