# CVE-2026-40968: Spring gRPC SecurityContext leaks across requests on authorization failure

> Authenticated identity leaks to subsequent unauthenticated requests on the same thread, allowing privilege escalation in Spring gRPC applications.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Apr 2026
- **Updated:** 28 Apr 2026
- **Also known as:** GHSA-4g9c-3x4p-mfpp

## What is CVE-2026-40968?

CVE-2026-40968 is a medium-severity authentication bypass vulnerability in Spring gRPC, published on 28 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-653 (Improper Isolation or Compartmentalization)

## Which versions are affected by CVE-2026-40968?

2 open source packages ship an affected version, including org.springframework.grpc:spring-grpc. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.springframework.grpc:spring-grpc` | Maven | All versions | 1.0.3 |
| `org.springframework.grpc:spring-grpc` | Maven | All versions | 1.0.3 |

Products: Vmware Spring Grpc.

## How do I fix CVE-2026-40968?

Upgrade org.springframework.grpc:spring-grpc to 1.0.3 or later.

## Is CVE-2026-40968 being exploited?

There is no known exploitation of CVE-2026-40968 in the wild and no public exploit code.

## Other vulnerabilities in Spring gRPC

- [CVE-2026-40969](https://insights.sbomify.com/CVE-2026-40969/): Spring gRPC AuthenticationException message reflected to remote client (low 3.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40968 and fix it if it is affected.

What it is: CVE-2026-40968 is a medium-severity authentication bypass vulnerability in Spring gRPC, published on 28 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-40968 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.springframework.grpc:spring-grpc (Maven): affected all versions; fixed in 1.0.3
- org.springframework.grpc:spring-grpc (Maven): affected all versions; fixed in 1.0.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-40968/ (Markdown: https://insights.sbomify.com/CVE-2026-40968/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40968
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40968
- OSV: https://osv.dev/vulnerability/CVE-2026-40968

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40968/
Summaries are generated and may contain mistakes; the official description above is the record.