CVE-2016-4437VulnerabilityPublished 11/03/2021Updated 10/24/2026

CVE-2016-4437: Apache Shiro Code Execution Vulnerability

Affects Apache ShiroSource CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 11/03/2021
KEV deadline: 05/03/2022
EPSS: 93.0% chance of exploitation in 30 days – higher than 99% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2016-4437 (opens in a new tab)

Description

Apache Shiro contains a vulnerability that allows remote attackers to execute code or bypass access restrictions if the "remember me" feature is used without configuring a cipher key. This vulnerability has been exploited in the wild and is considered high severity.

Summary

CVE-2016-4437 is a vulnerability in Apache Shiro where remote attackers can execute arbitrary code or bypass intended access controls via an unspecified request parameter. The issue arises when the "remember me" feature is enabled but no cipher key is configured, leading to insecure handling of authentication tokens.

Impact

Successful exploitation can lead to remote code execution or unauthorized access bypass, compromising the affected system's security. This vulnerability has been observed being exploited in the wild, indicating active threat usage.

Mitigation

No explicit patch or remediation details are provided in the available data. Users should verify their Apache Shiro configuration to ensure that a cipher key is properly set for the "remember me" feature. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance.

Weaknesses

CWE-284Improper Access Control (opens in a new tab)

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 09:41:52 UTC

Weaknesses

References

Related threats