CVE-2026-3418: Arbitrary File Upload via System REST API in Multiple WSO2 Products Allows Remote Code Execution

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-06 · updated 2026-08-31
Weakness: CWE-434

Description

The System REST API accepts user-supplied file uploads without enforcing sufficient validation on the file type or destination, allowing files to be written to arbitrary server-accessible locations. Exploitation requires authenticated administrative access with publisher privileges. Successful exploitation permits an authenticated publisher to upload files to server-accessible locations. Depending on the deployment environment and how uploaded files are handled, this could lead to the execution of uploaded content, potentially resulting in remote code execution.

Affected products

WSO2 API Manager: from 4.4.0 before 4.4.0.67; from 4.5.0 before 4.5.0.52; from 4.6.0 before 4.6.0.16 — fixed in 4.4.0.67, 4.5.0.52, 4.6.0.16
WSO2 API Control Plane: from 4.5.0 before 4.5.0.53; from 4.6.0 before 4.6.0.17 — fixed in 4.5.0.53, 4.6.0.17
WSO2 API Manager Publisher REST API V4: from 9.30.67 before 9.30.67.156; from 9.31.86 before 9.31.86.141; from 9.32.147 before 9.32.147.44 — fixed in 9.30.67.156, 9.31.86.141, 9.32.147.44, 9.33.104
WSO2 Carbon API Management API: from 9.30.67 before 9.30.67.156 — fixed in 9.30.67.156, 9.33.104
WSO2 Carbon API Management Implementation: from 9.30.67 before 9.30.67.156; from 9.31.86 before 9.31.86.141; from 9.32.147 before 9.32.147.44 — fixed in 9.30.67.156, 9.31.86.141, 9.32.147.44, 9.33.104
WSO2 Traffic Manager: from 4.5.0 before 4.5.0.51; from 4.6.0 before 4.6.0.16 — fixed in 4.5.0.51, 4.6.0.16
WSO2 Universal Gateway: from 4.5.0 before 4.5.0.52; from 4.6.0 before 4.6.0.16 — fixed in 4.5.0.52, 4.6.0.16

How to fix

Upgrade to a fixed version: WSO2 API Manager 4.4.0.67, 4.5.0.52, 4.6.0.16; WSO2 API Control Plane 4.5.0.53, 4.6.0.17; WSO2 API Manager Publisher REST API V4 9.30.67.156, 9.31.86.141, 9.32.147.44, 9.33.104; WSO2 Carbon API Management API 9.30.67.156, 9.33.104; WSO2 Carbon API Management Implementation 9.30.67.156, 9.31.86.141, 9.32.147.44, 9.33.104; WSO2 Traffic Manager 4.5.0.51, 4.6.0.16; WSO2 Universal Gateway 4.5.0.52, 4.6.0.16. Check the vendor advisory for mitigations.

References

https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5146/

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