CVE-2026-40968 PUBLISHED

Spring gRPC SecurityContext leaks across requests on authorization failure

Assigner: vmware
Reserved: 16.04.2026 Published: 28.04.2026 Updated: 28.04.2026

When an authenticated user is denied access to a gRPC method, their authenticated identity remains bound to the gRPC worker thread and can be inherited by a subsequent unauthenticated request on the same thread. This may allow the subsequent user to gain escalated permissions.

Affected versions: Spring gRPC: 1.0.0 - 1.0.2 (fixed in 1.0.3). Older, unsupported versions are also affected.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
CVSS Score: 4.3

Attack Vector	Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	Low
Privileges Required	Low	Integrity Impact	Low
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	Spring
Product	Spring gRPC
Versions	Default: unaffected affected from 1.0.0 to 1.0.3 (excl.)

References

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

Problem Types

CWE-653: Improper Isolation or Compartmentalization CWE

Impacts

A subsequent request on the same gRPC worker thread may inherit a prior user’s authenticated identity after an authorization failure, enabling privilege escalation (CVSS v3.1: low confidentiality and integrity impact).