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.
Fix
Public exploits 17
- 0dayCTF/CVE-2020-9484 PoC on GitHub
- AssassinUKG/CVE-2020-9484 PoC on GitHub
- ColdFusionX/CVE-2020-9484 PoC on GitHub
- DXY0411/CVE-2020-9484 PoC on GitHub
- DanQMoo/CVE-2020-9484-Scanner PoC on GitHub
- Disturbante/CVE-2020-9484 PoC on GitHub
- IdealDreamLast/CVE-2020-9484 PoC on GitHub
- PenTestical/CVE-2020-9484 PoC on GitHub
- RepublicR0K/CVE-2020-9484 PoC on GitHub
- VICXOR/CVE-2020-9484 PoC on GitHub
- anjai94/CVE-2020-9484-exploit PoC on GitHub
- d3fudd/CVE-2020-9484_Exploit PoC on GitHub
- masahiro331/CVE-2020-9484 PoC on GitHub
- qerogram/CVE-2020-9484 PoC on GitHub
- savsch/PoC_CVE-2020-9484 PoC on GitHub
- seanachao/CVE-2020-9484 PoC on GitHub
- threedr3am/tomcat-cluster-session-sync-exp PoC on GitHub
Each line links to the index that lists it, never to exploit code. Exploit-DB's "verified" and a Metasploit rank of good or better count as verified; a PoC-in-GitHub entry is a repository's claim.
Patch, vendor advisory and mitigation references on NVD 16
- https://lists.apache.org/thread.html/r77eae567ed829da9012cadb29af17f2df8fa23bf66faf88229857bb1%40%3Cannounce.tomcat.apache.org%3E Mailing List, Mitigation, Patch, Third Party Advisory
- https://www.oracle.com//security-alerts/cpujul2021.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuApr2021.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujan2021.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujan2022.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujul2020.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2020.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.html Patch, Third Party Advisory
- https://lists.apache.org/thread.html/r77eae567ed829da9012cadb29af17f2df8fa23bf66faf88229857bb1%40%3Cannounce.tomcat.apache.org%3E Mailing List, Mitigation, Patch, Third Party Advisory
- https://www.oracle.com//security-alerts/cpujul2021.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuApr2021.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujan2021.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujan2022.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujul2020.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2020.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.html Patch, Third Party Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 7.0 · apache, debian, opensuseNVD modified 2026-10-08 21:17
Affected (CPE criteria) 75
cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone1:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone10:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone11:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone12:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone13:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone14:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone15:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone16:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone17:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone18:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone19:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone2:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone20:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone21:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone22:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone23:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone24:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone25:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone26:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone27:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone3:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone4:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone5:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone6:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone7:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone8:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:9.0.0:milestone9:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:10.0.0:milestone1:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:10.0.0:milestone2:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:10.0.0:milestone3:*:*:*:*:*:*cpe:2.3:a:apache:tomcat:10.0.0:milestone4:*:*:*:*:*:*cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*- and 35 more
References 84
- http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00057.html Third Party Advisory
- http://packetstormsecurity.com/files/157924/Apache-Tomcat-CVE-2020-9484-Proof-Of-Concept.html Third Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2020/Jun/6 Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2021/03/01/2 Mailing List, Third Party Advisory
- https://kc.mcafee.com/corporate/index?page=content&id=SB10332 Third Party Advisory
- https://lists.apache.org/thread.html/r11ce01e8a4c7269b88f88212f21830edf73558997ac7744f37769b77%40%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r123b3ebe389f46f9d337923f393cdae4d3e9b78d982d706712f0898c%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/r26950738f4b4ca2d256597cf391d52d3450fa665c297ea5ca38f5469%40%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r77eae567ed829da9012cadb29af17f2df8fa23bf66faf88229857bb1%40%3Cannounce.tomcat.apache.org%3E Mailing List, Mitigation, Patch, Third Party Advisory
- https://lists.apache.org/thread.html/r7bc247fffcb1d58415215c861d2354bd653c86266230d78a93c71ae2%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r8a2ac0e476dbfc1e6440b09dcc782d444ad635d6da26f0284725a5dc%40%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r8dd19c514face6dd85fd4eab0271854883f40c7307926c1f7cd5400c%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/raa4123e472175bb052fbba165d37187cea923f755e8f3f30d124cb3f%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/rb1c0fb105ce2b93b7ec6fc1b77dd208022621a91c12d1f580813cfed%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rb51ccd58b2152fc75125b2406fc93e04ca9d34e737263faa6ff0f41f%40%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rc1778b38e74b5b6142414d57623bd55b023a72361f422836782fca3c%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rc8473b08abdf3c16494ed817bec1717a0ee0c8080315bc27db5f21c3%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/rf59c72572b9fee674a5d5cc6afeca4ffc3918a02c354a81cc50b7119%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/rf6d5d57b114678d8898005faef31e9fd6d7c981fcc4ccfc3bc272fc9%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rf70f53af27e04869bdac18b1fc14a3ee529e59eb12292c8791a77926%40%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rfe62fbf9d4c314f166fe8c668e50e5d9dd882a99447f26f0367474bf%40%3Cannounce.apache.org%3E
- https://lists.apache.org/thread.html/rfe62fbf9d4c314f166fe8c668e50e5d9dd882a99447f26f0367474bf%40%3Cannounce.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%3Cusers.tomcat.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2020/05/msg00020.html Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/05/msg00026.html Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/07/msg00010.html Mailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GIQHXENTLYUNOES4LXVNJ2NCUQQRF5VJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WJ7XHKWJWDNWXUJH6UB7CLIW4TWOZ26N/
- https://security.gentoo.org/glsa/202006-21 Third Party Advisory
- https://security.netapp.com/advisory/ntap-20200528-0005/ Third Party Advisory
- https://usn.ubuntu.com/4448-1/ Third Party Advisory
- https://usn.ubuntu.com/4596-1/ Third Party Advisory
- https://www.debian.org/security/2020/dsa-4727 Third Party Advisory
- https://www.oracle.com//security-alerts/cpujul2021.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuApr2021.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujan2021.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujan2022.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujul2020.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujul2022.html
- https://www.oracle.com/security-alerts/cpuoct2020.html Patch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.html Patch, Third Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00057.html Third Party Advisory
- http://packetstormsecurity.com/files/157924/Apache-Tomcat-CVE-2020-9484-Proof-Of-Concept.html Third Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2020/Jun/6 Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2021/03/01/2 Mailing List, Third Party Advisory
- https://kc.mcafee.com/corporate/index?page=content&id=SB10332 Third Party Advisory
- https://lists.apache.org/thread.html/r11ce01e8a4c7269b88f88212f21830edf73558997ac7744f37769b77%40%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r123b3ebe389f46f9d337923f393cdae4d3e9b78d982d706712f0898c%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/r26950738f4b4ca2d256597cf391d52d3450fa665c297ea5ca38f5469%40%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r77eae567ed829da9012cadb29af17f2df8fa23bf66faf88229857bb1%40%3Cannounce.tomcat.apache.org%3E Mailing List, Mitigation, Patch, Third Party Advisory
- https://lists.apache.org/thread.html/r7bc247fffcb1d58415215c861d2354bd653c86266230d78a93c71ae2%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r8a2ac0e476dbfc1e6440b09dcc782d444ad635d6da26f0284725a5dc%40%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r8dd19c514face6dd85fd4eab0271854883f40c7307926c1f7cd5400c%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/raa4123e472175bb052fbba165d37187cea923f755e8f3f30d124cb3f%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/rb1c0fb105ce2b93b7ec6fc1b77dd208022621a91c12d1f580813cfed%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rb51ccd58b2152fc75125b2406fc93e04ca9d34e737263faa6ff0f41f%40%3Cusers.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rc1778b38e74b5b6142414d57623bd55b023a72361f422836782fca3c%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rc8473b08abdf3c16494ed817bec1717a0ee0c8080315bc27db5f21c3%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/rf59c72572b9fee674a5d5cc6afeca4ffc3918a02c354a81cc50b7119%40%3Ccommits.tomee.apache.org%3E