CVE-2026-39418: CWE-918: Server-Side Request Forgery (SSRF) in 1Panel-dev MaxKB
CVE-2026-39418 is a Server-Side Request Forgery (SSRF) vulnerability in MaxKB versions 2. 7. 1 and below. It allows authenticated users with tool-editing permissions to bypass sandbox network protections and access internal services blocked by the sandbox's banned hosts configuration. The vulnerability arises because the sandbox hooks the connect() function to block connections, but the Linux sendto() syscall with the MSG_FASTOPEN flag can establish TCP connections without calling connect(), bypassing IP validation. This issue is fixed in MaxKB version 2. 8. 0.
AI Analysis
Technical Summary
MaxKB's sandbox network protection relies on LD_PRELOAD hooking of the connect() function to block connections to banned IP addresses. However, in versions 2.7.1 and earlier, an authenticated user with tool-editing permissions can exploit the Linux sendto() syscall with the MSG_FASTOPEN flag to establish TCP connections directly through the kernel, bypassing the connect() hook and IP validation. This enables Server-Side Request Forgery (SSRF) attacks to reach internal services that should be blocked by the sandbox. The vulnerability is addressed in MaxKB version 2.8.0.
Potential Impact
An authenticated user with tool-editing permissions can bypass sandbox network restrictions to access internal services that are explicitly blocked, potentially leading to unauthorized information disclosure or interaction with internal systems. The CVSS score is 5.0 (medium severity), indicating limited but meaningful impact on confidentiality, integrity, and availability.
Mitigation Recommendations
This vulnerability is fixed in MaxKB version 2.8.0. Users should upgrade to version 2.8.0 or later to remediate this issue. No other official remediation or temporary fixes are documented. Patch status is confirmed by the vendor's versioning information.
CVE-2026-39418: CWE-918: Server-Side Request Forgery (SSRF) in 1Panel-dev MaxKB
Description
CVE-2026-39418 is a Server-Side Request Forgery (SSRF) vulnerability in MaxKB versions 2. 7. 1 and below. It allows authenticated users with tool-editing permissions to bypass sandbox network protections and access internal services blocked by the sandbox's banned hosts configuration. The vulnerability arises because the sandbox hooks the connect() function to block connections, but the Linux sendto() syscall with the MSG_FASTOPEN flag can establish TCP connections without calling connect(), bypassing IP validation. This issue is fixed in MaxKB version 2. 8. 0.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
MaxKB's sandbox network protection relies on LD_PRELOAD hooking of the connect() function to block connections to banned IP addresses. However, in versions 2.7.1 and earlier, an authenticated user with tool-editing permissions can exploit the Linux sendto() syscall with the MSG_FASTOPEN flag to establish TCP connections directly through the kernel, bypassing the connect() hook and IP validation. This enables Server-Side Request Forgery (SSRF) attacks to reach internal services that should be blocked by the sandbox. The vulnerability is addressed in MaxKB version 2.8.0.
Potential Impact
An authenticated user with tool-editing permissions can bypass sandbox network restrictions to access internal services that are explicitly blocked, potentially leading to unauthorized information disclosure or interaction with internal systems. The CVSS score is 5.0 (medium severity), indicating limited but meaningful impact on confidentiality, integrity, and availability.
Mitigation Recommendations
This vulnerability is fixed in MaxKB version 2.8.0. Users should upgrade to version 2.8.0 or later to remediate this issue. No other official remediation or temporary fixes are documented. Patch status is confirmed by the vendor's versioning information.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-07T00:23:30.595Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69dd958882d89c981f9c581b
Added to database: 4/14/2026, 1:16:56 AM
Last enriched: 4/14/2026, 1:32:26 AM
Last updated: 4/14/2026, 7:35:36 AM
Views: 7
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