CVE-2016-8735
CVE-2016-8735 is a security flaw in Apache Tomcat, a server for running Java web applications. Attackers can run their own code on Apache Tomcat. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 12 May 2023.[1]
Apache Tomcat is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Apache has published a fix or advice.
Description
CISA calls it a remote code execution in Apache Tomcat. In its words: “Apache Tomcat contains an unspecified vulnerability that allows for remote code execution if JmxRemoteLifecycleListener is used and an attacker can reach Java Management Extension (JMX) ports. This CVE exists because this listener wasn't updated for consistency with the Oracle patched issues for CVE-2016-3427 which affected credential types.”[1]
The underlying weakness is improper access control (CWE-284), in MITRE’s list of common software weaknesses.[2]
It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Apache’s advisory has them[3]. CISA names the product as Apache Tomcat.
Most families won’t have Apache Tomcat; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 12 May 2023, 2,227 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 2 Jun 2023 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 90%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Apache has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Apache Tomcat is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 2 Jun 2023 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 90%.[4] |
See also
Other Apache Tomcat flaws
- CVE-2026-34486: missing encryption of sensitive data ·
- CVE-2025-24813: path equivalence ·
- CVE-2017-12617: remote code execution ·
- CVE-2017-12615: on windows remote code execution ·
- CVE-2020-1938: improper privilege management ·
Other Apache flaws
- CVE-2016-3081, Apache Struts: command injection ·
- CVE-2026-34197, Apache ActiveMQ: improper input validation ·
- CVE-2024-38475, Apache HTTP Server: improper escaping of output ·
- CVE-2024-45195, Apache OFBiz: forced browsing ·
- CVE-2024-27348, Apache HugeGraph-Server: improper access control ·
Other improper access control flaws
- CVE-2015-3306, ProFTPD: improper access control ·
- CVE-2026-21962, Oracle HTTP Server and Oracle Weblogic Server Proxy Plug-in: improper access control ·
- CVE-2026-56290, Joomlack Page Builder: improper access control ·
- CVE-2026-34908, Ubiquiti UniFi OS: improper access control ·
- CVE-2026-48907, Widget Factory Joomla Content Editor: improper access control ·
Added the same day
- CVE-2023-25717, Ruckus Wireless products: multiple ruckus wireless products CSRF and RCE ·
- CVE-2021-3560, Red Hat Polkit: incorrect authorization ·
- CVE-2016-3427, Oracle Java SE and JRockit: unspecified ·
- CVE-2015-5317, Jenkins User Interface (UI): user interface (UI) information disclosure ·
- CVE-2014-0196, Linux Kernel: race condition ·
Every Apache flaw on CISA’s list · Everything added in May 2023
References
- ^ Cybersecurity and Infrastructure Security Agency. “Apache Tomcat Remote Code Execution Vulnerability”. Known Exploited Vulnerabilities Catalog, added 12 May 2023.
- ^ National Institute of Standards and Technology. “CVE-2016-8735 Detail”. National Vulnerability Database, published 6 Apr 2017.
- ^ Apache. Advisories and fixes: tomcat.apache.org, lists.apache.org, lists.apache.org, lists.apache.org, lists.apache.org, and 3 more on NVD’s record.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.903, percentile 99.8, 31 Oct 2026.
- CVE Program. “CVE-2016-8735”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.