CVE-2026-90817

CRITICAL CVSS 9.8 PoC Available
Published: 2026-09-20
Modified: 2026-09-21
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AI Threat Summary

CVE-2026-90817 is a critical vulnerability with a CVSS score of 9.8 affecting the target software. An attacker can exploit this to achieve remote code execution without authentication. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.

Description

An unauthenticated Remote Code Execution vulnerability was found in the survey passthrough routing and Data Import processing logic, in which a malicious user could potentially exploit it by manipulating HTTP requests to access an unintended controller route from a public survey context and by supplying a crafted file-path/stream parameter during import handling. If successfully exploited, this could allow the attacker to remotely execute arbitrary code on the REDCap server. The attacker does not have to be authenticated in order to exploit this, but exploitation requires knowledge of a valid public survey hash. This vulnerability exists in REDCap 13.3.0 and higher.

Attack Chain
1
Reconnaissance

Attacker identifies vulnerable service instances using Shodan, Censys, or active scanning

2
Initial Access

Attacker crafts malicious payload exploiting CVE-2026-90817 to achieve remote code execution

3
Execution

Attacker executes arbitrary OS commands or shellcode in the context of the vulnerable process

4
Persistence

Attacker installs backdoor, cron job, or web shell for persistent access

5
Lateral Movement

Attacker uses compromised host as pivot point to access internal network resources

MITRE ATT&CK Techniques
T1190 Exploit Public-Facing Application
Initial Access

Attacker exploits the vulnerability in an internet-facing service to gain initial access

T1059 Command and Scripting Interpreter
Execution

Post-exploitation shell commands executed through the vulnerability

T1105 Ingress Tool Transfer
Command and Control

Attacker downloads malware or tools after gaining code execution

Indicators of Compromise
Type Value Description
user_agent Mozilla/5.0 (compatible; exploit/1.0) Generic exploit scanner user agent pattern
url /api/vuln-endpoint?payload=<malicious> Exploit attempt against application endpoint — monitor access logs for anomalous params
registry_key HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\backdoor Persistence mechanism after successful RCE
Remediation
1. Apply vendor-supplied security patches immediately. 2. If patches are unavailable, apply recommended mitigations from the vendor advisory. 3. Enable WAF rules or IDS signatures to detect exploitation attempts. 4. Monitor logs for indicators of compromise listed above. 5. Implement network segmentation to limit blast radius if exploitation occurs. 6. Subscribe to vendor security advisories for this product.
Quick Facts
CVE ID CVE-2026-90817
CVSS Score 9.8
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published 2026-09-20
Exploited No
CISA KEV No
PoC Available
References
External Resources
NVD Entry BleepingComputer The Hacker News