CVE-2016-4437: in the CISA KEV catalogue
Apache Shiro Code Execution Vulnerability. CISA added CVE-2016-4437 to the Known Exploited Vulnerabilities catalogue on 2021-11-03 with a default due date of 2022-05-03. Known ransomware campaign use: Unknown. Forensic triage flag: No.
Apache Shiro contains a vulnerability which may allow remote attackers to execute code or bypass intended access restrictions via an unspecified request parameter when a cipher key has not been configured for the "remember me" feature. (CISA description)
- Vendor / product
- Apache Shiro
- CWE
- CWE-284
- CISA required action
- Apply updates per vendor instructions.
- EPSS
- 93%, percentile 99 (scored 2026-11-03)
EPSS puts about 93 in 100 odds (93%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 99% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.
Vendor and reference links (from CISA)
Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.
Frequently asked questions
Is CVE-2016-4437 in the CISA KEV catalogue?
Yes. CISA added CVE-2016-4437 (Apache Shiro Code Execution Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2021-11-03. CISA's default due date for it is 2022-05-03.
Is CVE-2016-4437 used in ransomware attacks?
CISA marks known ransomware campaign use as Unknown for CVE-2016-4437. That means CISA lacks confirmation, not that ransomware groups do not use it.
What should I do about CVE-2016-4437?
CISA's required action: Apply updates per vendor instructions.
Sources
- CISA, Known Exploited Vulnerabilities Catalog (accessed 2026-11-03)
- FIRST, Exploit Prediction Scoring System (EPSS) (EPSS by FIRST; scores generated by Empirical Security)
- NVD record for CVE-2016-4437