Threats / Apache / CVE-2017-9791
CVE-2017-9791
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Apache Struts 1 vulnerability
Apache Struts 1 plugin allows remote code execution through improper validation of malicious field values in ActionMessage objects.
Verdict
Today item — known-exploited.
A remote attacker can execute arbitrary code on systems running vulnerable Apache Struts 1 by crafting malicious input that bypasses field validation. The vulnerability has been actively exploited in the wild.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
2 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-02-10).
Probability (EPSS)
EPSS 0.98931 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Apache, Struts 1. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-20 Improper Input Validation.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious field value and send it in a raw message to the ActionMessage handler.
Business
The application receives untrusted input without proper validation, creating an entry point for code execution.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I exploit the insufficient input validation to inject code that the application processes.
Business
The validation bypass allows my payload to reach the execution layer instead of being rejected.
3
Lateral reach — past segmentation narrative 3
Attacker
I achieve remote code execution on the target system with the privileges of the application process.
Business
The organization loses control of affected systems, exposing sensitive data and enabling lateral movement through the network.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05