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Vulnerabilities

Vulnerability · CVE-2020-9484

When using Apache Tomcat versions 10.0.0-M1 to 10.0.0-M4, 9.0.0.M1 to 9.0.34, 8.5.0 to 8.5.54 and 7.0.0 to 7.0.103 if a) an attacker is able to control the contents an…

Published May 20, 2020 · catalog updated Oct 8, 2026 · Oracle

Check this week

CVE-2020-9484 is not in CISA KEV. FIRST estimates a 55.52% chance of exploitation in the next 30 days. Check whether you run Oracle.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.0
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
55.52%
Remediation
Advisory link
Affected products
cpe apache/tomcat

When using Apache Tomcat versions 10.0.0-M1 to 10.0.0-M4, 9.0.0.M1 to 9.0.34, 8.5.0 to 8.5.54 and 7.0.0 to 7.0.103 if a) an attacker is able to control the contents and name of a file on the server; and b) the server is configured to use the PersistenceManager with a FileStore; and c) the PersistenceManager is configured with sessionAttributeValueClassNameFilter="null" (the default unless a SecurityManager is used) or a sufficiently lax filter to allow the attacker provided object to be deserialized; and d) the attacker knows the relative file path from the storage location used by FileStore to the file the attacker has control over; then, using a specifically crafted request, the attacker will be able to trigger remote code execution via deserialization of the file under their control. Note that all of conditions a) to d) must be true for the attack to succeed.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe apache/tomcat9.0.0

How to fix CVE-2020-9484

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2020-9484 is not in CISA KEV. FIRST estimates a 55.52% chance of exploitation in the next 30 days. Check whether you run Oracle.

Which versions are affected?

Compare what you have installed with 9.0.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-502: Deserialization of Untrusted Data. EPSS 55.52%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. May 20, 2020 · Oracle Critical Patch Updates

    Detected

    When using Apache Tomcat versions 10.0.0-M1 to 10.0.0-M4, 9.0.0.M1 to 9.0.34, 8.5.0 to 8.5.54 and 7.0.0 to 7.0.103 if a) an attacker is able to control the contents and name of a file on the server; and b) the server is configured to use the PersistenceManager with a FileStore; and c) the PersistenceManager is configured with sessionAttributeValueClassNameFilter="null" (the default unless a Securi

  2. Oct 8, 2026 · Oracle Critical Patch Updates

    Updated

    When using Apache Tomcat versions 10.0.0-M1 to 10.0.0-M4, 9.0.0.M1 to 9.0.34, 8.5.0 to 8.5.54 and 7.0.0 to 7.0.103 if a) an attacker is able to control the contents and name of a file on the server; and b) the server is configured to use the PersistenceManager with a FileStore; and c) the PersistenceManager is configured with sessionAttributeValueClassNameFilter="null" (the default unless a Securi

Sources

  • CVE.orgVulnerability recordCVE-2020-9484

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2020-9484

    30-day exploitation probability 55.5%

    first.org
  • Oracle Critical Patch UpdatesVendor advisoryCVE-2020-9484

    When using Apache Tomcat versions 10.0.0-M1 to 10.0.0-M4, 9.0.0.M1 to 9.0.34, 8.5.0 to 8.5.54 and 7.0.0 to 7.0.103 if a) an attacker is able to control the contents and name of a file on the server; and b) the server is configured to use the PersistenceManager with a FileStore; and c) the PersistenceManager is configured with sessionAttributeValueClassNameFilter="null" (the default unless a Securi

    nvd.nist.gov
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/157924/Apache-Tomcat-CVE-2020-9484-Proof-Of-Concept.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.