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HIGH

CVE-2020-9484

CVSS v3

7

HIGH

EPSS Score

55.5 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • org.apache.tomcat:tomcat-catalinaMavenfrom 7.0.0 · fixed in 7.0.104and 1 other package
  • tomcatBitnamifrom 7.0.0 · fixed in 7.0.108

Vendor advisories

  • CVE-2020-9484 Red Hat Product Security199 products fixed · 5 known affected

    tomcat: deserialization flaw in session persistence storage leading to RCE

    pki-servlet-4.0-api (pki-deps:10.6) as a component of Red Hat Enterprise Linux 8 · pki-servlet-engine.src (pki-deps:10.6) as a component of Red Hat Enterprise Linux 8 · pki-servlet-engine (pki-deps:10.6) as a component of Red Hat Enterprise Linux 8

  • RHSA-2022:5532 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Fuse 7.11.0 release and security update

  • RHSA-2021:3140 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Fuse 7.9.0 release and security update

  • RHSA-2020:3017 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat support for Spring Boot 2.1.15 security and bug fix update

  • RHSA-2020:2530 Red Hat Product Security50 products fixed

    Red Hat Security Advisory: tomcat security update

  • RHSA-2020:2529 Red Hat Product Security40 products fixed

    Red Hat Security Advisory: tomcat6 security update

4 more advisories

Full record on NVD

Description

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2020-05-20
Last Modified
2026-08-25

Frequently asked questions

What is 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 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.

Is CVE-2020-9484 actively exploited?

Active exploitation of CVE-2020-9484 has not been confirmed. Its EPSS score was 55.5% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-9484?

CVE-2020-9484 has a CVSS v3 base score of 7 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

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