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
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…
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CVE-2020-9484 at a glance
- CISA KEV
- Not listed (catalog checked )
- Vendor advisories
- 2 from Apache
- VulniPulse record
- Published · Updated
Is CVE-2020-9484 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2020-9484 is not in the CISA KEV catalog (checked ) and no tracked advisory for it reports exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2020-9484?
The tracked advisories that cover only this CVE do not list a fixed release yet. That does not mean no fix exists; check each vendor source below.
Vendor advisory comparison
Apache
2 advisories- Advisory severityUnrated
Advisory [CVE-2020-9484 +2] Incomplete fix for CVE-2020-9484
CVE-2021-25329Source published Source updated
This bulletin covers 3 CVEs. The products, versions, score and guidance below describe the bulletin; check its source for applicability to this specific CVE.
The fix for CVE-2020-9484 was incomplete. When using Apache Tomcat 10.0.0-M1 to 10.0.0, 9.0.0.M1 to 9.0.41, 8.5.0 to 8.5.61 or 7.0.0. to 7.0.107 with a configuration edge case that was highly unlikely to be used, the Tomcat instance was still vulnerable to CVE-2020-9494. Note that both the previously published prerequisites for CVE-2020-9484 and the previously published mitigations for CVE-2020-9484 also apply to this issue.
- Affected products in this advisory
- Apache Tomcat
- Source-reported affected versions
- Apache Tomcat Apache Tomcat 10 before 10.0.0
- Apache Tomcat Apache Tomcat 9 before 9.0.41
- Apache Tomcat Apache Tomcat 8.5 before 8.5.61
- Apache Tomcat Apache Tomcat 7 before 7.0.107
- Source-reported fixed versions
- 10.0.0
- 9.0.41
- 8.5.61
- 7.0.107
- Mitigation guidance
- Note that both the previously published prerequisites for CVE-2020-9484 and the previously published mitigations for CVE-2020-9484 also apply to this issue.
- Advisory severityUnrated
Advisory [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
CVE-2020-9484Source published Source 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 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.…
- Affected products in this advisory
- Apache Tomcat
- Source-reported affected versions
- Apache Tomcat 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
- Source-reported fixed versions
- No fixed-version detail extracted. This does not mean no fix exists.
- Mitigation guidance
- No mitigation guidance extracted; consult the source.
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