CVE-2017-9791VulnerabilityPublished 02/10/2022Updated 10/24/2026

CVE-2017-9791: Apache Struts 1 Improper Input Validation Vulnerability

Affects Apache Struts 1Source CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 02/10/2022
KEV deadline: 08/10/2022
EPSS: 98.9% 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-2017-9791 (opens in a new tab)

Description

CVE-2017-9791 is a high severity vulnerability in Apache Struts 1 where improper input validation in the Struts 1 plugin can allow remote code execution. This occurs when a malicious field value is passed in a raw message to the ActionMessage component. The vulnerability has been exploited in the wild.

Summary

The Struts 1 plugin in Apache Struts suffers from improper input validation that may allow an attacker to execute arbitrary code remotely by sending a crafted field value within a raw message to the ActionMessage. This vulnerability is identified as CVE-2017-9791 and is associated with CWE-20 (Improper Input Validation). It has been confirmed to be exploited in the wild.

Impact

Successful exploitation of this vulnerability can lead to remote code execution on affected systems running Apache Struts 1, potentially allowing attackers to take control of the affected server or execute arbitrary commands.

Mitigation

No patch or official fix information is provided in the available data. Patch status is not yet confirmed — check the Apache vendor advisory for current remediation guidance. Given the known exploitation in the wild, affected organizations should prioritize verifying their Apache Struts 1 installations and apply any available updates or mitigations from Apache.

Weaknesses

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

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 10:11:19 UTC

Weaknesses

References

Related threats