CVE-2018-11776VulnerabilityPublished 11/03/2021Updated 10/24/2026

CVE-2018-11776: Apache Struts Remote Code Execution Vulnerability

Affects Apache StrutsSource 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: 100.0% 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-2018-11776 (opens in a new tab)

Description

CVE-2018-11776 is a high severity remote code execution vulnerability in Apache Struts. It occurs under specific configuration conditions involving the alwaysSelectFullNamespace option and namespace settings in package configurations. Exploitation allows attackers to execute arbitrary code remotely. This vulnerability has been exploited in the wild.

Summary

Apache Struts contains a remote code execution vulnerability identified as CVE-2018-11776. The flaw manifests when the alwaysSelectFullNamespace option is set to true and a result value is not set in underlying configurations, while the upper package configuration has no or wildcard namespace. Alternatively, it can be triggered using a URL tag without a value and action set, combined with an upper package configuration having no or wildcard namespace. These conditions allow attackers to execute arbitrary code remotely.

Impact

Successful exploitation of this vulnerability enables remote attackers to execute arbitrary code on affected Apache Struts servers. This can lead to full system compromise, data breaches, and disruption of services. The vulnerability has been observed to be exploited in the wild, indicating active threat usage.

Mitigation

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is confirmed, review Apache Struts configurations to avoid the vulnerable conditions described, specifically regarding the alwaysSelectFullNamespace option and namespace settings. Monitor vendor communications for patches or official mitigations.

Weaknesses

CWE-20Improper Input Validation (opens in a new tab)

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 09:41:42 UTC

Weaknesses

References

Related threats