Spring gRPC AuthenticationException message reflected to remote client

published 2026-04-28 6 mo ago modified 2026-10-26 14 d ago also GHSA-37w2-q6vh-45v6 , EUVD-2026-26064

cvss: 3.7; 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 9%
public exploits: 0; none known

The raw message of every server-side AuthenticationException is returned to the unauthenticated remote caller in the gRPC status description. This allows an attacker to obtain information about the authentication failure, which may be useful for further attacks.

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

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	3.7	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
GitHub	3.1	3.7	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/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-209 Generation of Error Message Containing Sensitive Information

References

spring.io /security/cve-2026-40969
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-40969
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