---
id: CVE-2020-9493
title: >-
  A deserialization flaw was found in Apache Chainsaw versions prior to 2.1.0
  which could lead to malicious code execution.
summary: >-
  A deserialization flaw was found in Apache Chainsaw versions prior to 2.1.0
  which could lead to malicious code execution.
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-502
vendor: apache
product: chainsaw
affected:
  - chainsaw < 2.1.0
  - 'log4j >= 1.2, < 2.0'
  - reload4j < 1.2.18.1
patched:
  - chainsaw 2.1.0
  - log4j 2.0
  - reload4j 1.2.18.1
published: '2021-06-16'
updated: '2026-10-07'
sourceUpdated: '2026-10-07T16:17:30.130'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-9493'
references:
  - url: 'http://www.openwall.com/lists/oss-security/2021/06/16/1'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2022/01/18/5'
    label: security@apache.org
  - url: >-
      https://lists.apache.org/thread.html/r50d389c613ba6062a26aa57e163c09bfee4ff2d95d67331d75265b83%40%3Cannounce.apache.org%3E
    label: security@apache.org
  - url: 'https://www.openwall.com/lists/oss-security/2021/06/16/1'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2021/06/16/1'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://www.openwall.com/lists/oss-security/2022/01/18/5'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.apache.org/thread.html/r50d389c613ba6062a26aa57e163c09bfee4ff2d95d67331d75265b83%40%3Cannounce.apache.org%3E
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.openwall.com/lists/oss-security/2021/06/16/1'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-07T15:59:41.130111Z'
epss: 0.04612
epssPercentile: 0.9142
ingestedAt: '2026-10-07T16:38:22.198Z'
---

## Overview

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

## Affected

- `chainsaw < 2.1.0`
- `log4j >= 1.2, < 2.0`
- `reload4j < 1.2.18.1`

## Remediation

Upgrade past the affected range:

- `chainsaw 2.1.0`
- `log4j 2.0`
- `reload4j 1.2.18.1`