CVE-2017-5638 Vulnerability
Published: 12/16/2025
Written by: Lizzie Danielson
What is CVE-2017-5638 vulnerability?
CVE-2017-5638 is a critical remote code execution (RCE) vulnerability in Apache Struts 2, identified as a flaw in the Jakarta Multipart parser. This vulnerability allows attackers to execute arbitrary commands on affected servers by exploiting improper exception handling during file uploads. Due to its severe potential consequences, CVE-2017-5638 has been widely exploited in the wild since its disclosure.
When was it discovered?
CVE-2017-5638 was publicly disclosed on March 6, 2017, with credits for its discovery attributed to the Apache Struts security team. Exploitation in real-world scenarios, including major campaigns, occurred almost immediately after the vulnerability's disclosure, highlighting its impact and urgency for patching.
Affected products & versions
Product | Versions Affected | Fixed Versions / Patch Links |
Apache Struts 2 | Versions 2.3.5 - 2.3.31, 2.5 - 2.5.10 |
CVE-2017-5638 technical description
CVE-2017-5638 stems from an exception-handling issue within the Jakarta Multipart parser in Apache Struts. Attackers craft a malicious Content-Type value in HTTP headers, which is improperly evaluated due to flawed exception handling. This bypasses security mechanisms, enabling arbitrary code execution on the server. Notably, this can affect critical applications relying on Apache Struts 2 frameworks, exposing sensitive organizational assets to severe threats.
Tactics, Techniques and Procedures (TTPs)
Adversaries utilize CVE-2017-5638 through HTTP POST requests with malicious headers targeting exposed Apache Struts endpoints. Their approach often involves scanning for vulnerable systems, uploading payloads, and executing privilege escalation techniques to maximize damage.
Indicators of compromise
Malicious HTTP Content-Type headers in server logs
Unusual outbound connections or executed shell commands
Unauthorized modifications to sensitive server files or configurations
Known proof-of-concepts &exploits
Multiple proof-of-concepts (PoCs) targeting CVE-2017-5638 have circulated widely in public exploit repositories. Exploitation has been observed across various industries, with attackers leveraging automation tools to identify unpatched systems quickly.
How to detect CVE-2017-5638 vulnerability?
Detection begins with scanning for the presence of vulnerable Apache Struts versions. Security Information and Event Management (SIEM) tools should be configured to monitor HTTP Content-Type anomalies. Reviewing server logs for suspicious commands and abnormal system behaviors aids in identifying compromise indicators.
Impact & risk of CVE-2017-5638 vulnerability
This vulnerability severely compromises data confidentiality, integrity, and availability for affected systems. Attackers can execute high-impact actions such as delivering ransomware, stealing sensitive data, or disrupting business operations. CVE-2017-5638 illustrates how web-facing applications can turn into entry points for devastating attacks.
Mitigation & remediation strategies
Organizations should urgently patch to the fixed Apache Struts versions. If immediate patching isn't feasible, implement strict access controls, disable file upload functionality where possible, and deploy web application firewalls (WAFs) to block malicious traffic targeting this vulnerability.
CVE-2017-5638 Vulnerability FAQs
CVE-2017-5638 is a critical RCE vulnerability in Apache Struts 2 that allows remote attackers to execute arbitrary commands by exploiting improper exception handling in HTTP Content-Type headers. Its exploitation can lead to significant damage, including system compromise and data theft.
The vulnerability affects systems running unpatched versions of Apache Struts. Attackers can manipulate HTTP headers to execute unauthorized commands on the underlying server, potentially exposing sensitive data and enabling further malicious activities.
While most systems have been patched, systems running legacy software remain at risk. Businesses should ensure all dependencies are up to date and monitor network traffic for any signs of exploitation attempts.
Organizations can protect themselves by deploying patched versions of Apache Struts, eliminating unnecessary network exposure, and using web application firewalls (WAFs) to mitigate exploit attempts. Implementing robust monitoring tools helps detect and respond to potential threats.
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