CVE-2020-9484Public exploit

Remote code execution via FileStore session deserialization

Published May 20, 2020 · Updated Aug 4, 2024

Deserialization in affected Apache Tomcat releases allows attackers to execute code through a crafted session request. FileStore derives a disk path from the requested session identifier and deserializes the referenced session file without first confining it to the configured store directory. Exploitation requires attacker-controlled file contents and name, PersistentManager with FileStore, a permissive class filter, and knowledge of the relative file path.

CVSS severity7.0
High
EPSS probability56.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in affected Apache Tomcat releases allows attackers to execute code through a crafted session request. FileStore derives a disk path from the requested session identifier and deserializes the referenced session file without first confining it to the configured store directory. Exploitation requires attacker-controlled file contents and name, PersistentManager with FileStore, a permissive class filter, and knowledge of the relative file path.

The record

CVE
CVE-2020-9484
Published
May 20, 2020
Updated
Aug 4, 2024
Vendor
The Apache Software Foundation
Product
Apache Tomcat
Classifications
CWE-502, T1190
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 20, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Apache Tomcat 10.0.0-M1 to 10.0.0-M4, 9.0.0.M1 to 9.0.34, 8.5.0 to 8.5.54, 7.0.0 to 7.0.103

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Apache Software Foundation · Apache Tomcatversion=Apache Tomcat 10.0.0-M1 to 10.0.0-M4, 9.0.0.M1 to 9.0.34, 8.5.0 to 8.5.54, 7.0.0 to 7.0.103

Published CVSS scores

7.0NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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