Potential remote code execution in 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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.apache.tomcat.embed:tomcat-embed-core | >= 10.0.0-M1, < 10.0.0-M5, >= 9.0.0, < 9.0.35, >= 8.0.0, < 8.5.55, >= 7.0.0, < 7.0.104 | 10.0.0-M5, 9.0.35, 8.5.55, 7.0.104 |
| Java / Kotlin (Maven) | org.apache.tomcat:tomcat-catalina | >= 10.0.0-M1, < 10.0.0-M5, >= 9.0.0, < 9.0.35, >= 8.0.0, < 8.5.55, >= 7.0.0, < 7.0.104 | 10.0.0-M5, 9.0.35, 8.5.55, 7.0.104 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2020-9484
- https://github.com/apache/tomcat/commit/3aa8f28db7efb311cdd1b6fe15a9cd3b167a2222.patch
- https://github.com/apache/tomcat/commit/4785433a226a20df6acbea49296e1ce7e23de453
- https://github.com/apache/tomcat/commit/6d66e99ef85da93e4d2c2a536ca51aa3418bfaf4
- https://github.com/apache/tomcat/commit/74b105657ffbd1d1de80455f03446c3bbf30d1f5
- https://github.com/apache/tomcat/commit/93f0cc403a9210d469afc2bd9cf03ab3251c6f35
- https://github.com/apache/tomcat/commit/bb33048e3f9b4f2b70e4da2e6c4e34ca89023b1b
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WJ7XHKWJWDNWXUJH6UB7CLIW4TWOZ26N
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GIQHXENTLYUNOES4LXVNJ2NCUQQRF5VJ
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WJ7XHKWJWDNWXUJH6UB7CLIW4TWOZ26N
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GIQHXENTLYUNOES4LXVNJ2NCUQQRF5VJ
- https://lists.debian.org/debian-lts-announce/2020/07/msg00010.html
- https://lists.debian.org/debian-lts-announce/2020/05/msg00026.html
- https://lists.debian.org/debian-lts-announce/2020/05/msg00020.html
- https://lists.apache.org/thread.html/rfe62fbf9d4c314f166fe8c668e50e5d9dd882a99447f26f0367474bf@%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rfe62fbf9d4c314f166fe8c668e50e5d9dd882a99447f26f0367474bf@%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rfe62fbf9d4c314f166fe8c668e50e5d9dd882a99447f26f0367474bf@%3Cannounce.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rfe62fbf9d4c314f166fe8c668e50e5d9dd882a99447f26f0367474bf@%3Cannounce.apache.org%3E
- https://lists.apache.org/thread.html/rfe62fbf9d4c314f166fe8c668e50e5d9dd882a99447f26f0367474bf%40%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rfe62fbf9d4c314f166fe8c668e50e5d9dd882a99447f26f0367474bf%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rfe62fbf9d4c314f166fe8c668e50e5d9dd882a99447f26f0367474bf%40%3Cannounce.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rfe62fbf9d4c314f166fe8c668e50e5d9dd882a99447f26f0367474bf%40%3Cannounce.apache.org%3E
- https://www.oracle.com/security-alerts/cpuoct2020.html
- https://www.oracle.com/security-alerts/cpujul2022.html
- https://www.oracle.com/security-alerts/cpujul2020.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpujan2021.html
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://www.debian.org/security/2020/dsa-4727
- https://usn.ubuntu.com/4596-1
- https://usn.ubuntu.com/4448-1
- https://tomcat.apache.org/security-9.html
- https://tomcat.apache.org/security-8.html
- https://tomcat.apache.org/security-7.html
- https://tomcat.apache.org/security-10.html
- https://security.netapp.com/advisory/ntap-20200528-0005
- https://security.gentoo.org/glsa/202006-21
- https://lists.apache.org/thread.html/r8dd19c514face6dd85fd4eab0271854883f40c7307926c1f7cd5400c@%3Ccommits.tomee.apache.org%3E
- CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-502- Platform
- Java / Kotlin (Maven)
- Package
org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat:tomcat-catalina- Disclosed
- 21.05.2020
- Updated
- 11.10.2026 12:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-344f-f5vg-2jfj - CC BY 4.0
Vulnerability history: org.apache.tomcat.embed:tomcat-embed-core
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 77
- First → latest
- 10.2018 08.2026
- Without a fix
- 0
- Exploited in attacks
- 5
Severity breakdown
- Critical 11
- High 36
- Medium 25
- Low 5
Disclosures per year
- 2018: 8
- 2019: 5
- 2020: 5
- 2021: 3
- 2022: 7
- 2023: 9
- 2024: 7
- 2025: 15
- 2026: 18
-
Potential remote code execution in Apache Tomcat this entry
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