Spring gRPC SecurityContext leaks across requests on authorization failure

published 2026-04-28 6 mo ago modified 2026-10-26 13 d ago also GHSA-4g9c-3x4p-mfpp , EUVD-2026-26054

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits: 0; none known

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.

Patch / fix

fixed in 2

maven org.springframework.grpc:spring-grpc 1.0.3
Spring Spring gRPC 1.0.3

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 6 mo ago (2026-04-28)

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.3	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
NVD	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
GitHub	3.1	4.2	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
maven	org.springframework.grpc:spring-grpc	<1.0.3	1.0.3

Affected products

Spring Spring gRPC

Classification

Weakness

CWE-653 Improper Isolation or Compartmentalization

References

spring.io /security/cve-2026-40968
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-40968
advisory
github.com /spring-projects/spring-grpc
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary