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MEDIUM severity

CVE-2026-40968 — spring-grpc

MEDIUM

CVE-2026-40968 is a medium-severity (CVSS 4.2) CWE-653 vulnerability in org.springframework.grpc:spring-grpc. A fix is available for org.springframework.grpc:spring-grpc — see the affected versions and patch details below.

Spring gRPC SecurityContext leaks across requests on authorization failure

Also known asGHSA-4g9c-3x4p-mfpp
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40968.

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs7th percentile — riskier than 7% of all scored CVEsHighest risk
0.00%0.27%0.54%0.80%0.0%0.2%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
☕org.springframework.grpc:spring-grpc

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.springframework.grpc:spring-grpcall versions1.0.3org.springframework.grpc:spring-grpc:1.0.3

Affected Products

1 product · 1 configurations
Application
spring grpcvmware
< 1.0.3
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.springframework.grpc:spring-grpc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.springframework.grpc:spring-grpc to 1.0.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40968 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

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CVE-2026-40968: spring-grpc — Fixed in 1.0.3