SB20260428204 - Multiple vulnerabilities in Spring gRPC

Description

This security bulletin contains information about 2 vulnerabilities.

1) Improper access control (CVE-ID: CVE-2026-40968)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a remote user to escalate privileges.

The vulnerability exists due to improper access control in the gRPC worker thread SecurityContext handling when processing a subsequent unauthenticated request after an authorization failure. A remote user can send a request on a reused worker thread to escalate privileges.

The issue occurs when an authenticated identity remains bound to the worker thread after access to a gRPC method is denied.

2) Information Exposure Through an Error Message (CVE-ID: CVE-2026-40969)

CWE-ID: CWE-209 - Information Exposure Through an Error Message

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a remote attacker to disclose sensitive information.

The vulnerability exists due to information exposure through an error message in the gRPC status description when returning server-side AuthenticationException details to the client. A remote attacker can trigger an authentication failure to disclose sensitive information.

Remediation

Install update from vendor's website.

References

• https://spring.io/security/cve-2026-40968
• https://spring.io/security/cve-2026-40969