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. The issue arises because the sandbox network protection can be bypassed using the socket. sendto() function with the MSG_FASTOPEN flag, allowing authenticated users with tool-editing permissions to access internal services blocked by the sandbox. This bypass occurs because the sandbox hooks the connect() function to block banned IPs, but sendto() with MSG_FASTOPEN establishes TCP connections without calling connect(), circumventing IP validation. The vulnerability has been fixed in MaxKB version 2. 8. 0. The CVSS score is 5.
AI Analysis
Technical Summary
MaxKB's sandbox network protection relies on hooking the connect() function via LD_PRELOAD to block connections to banned IP addresses. However, in versions 2.7.1 and earlier, an authenticated user with tool-editing permissions can bypass this restriction by using socket.sendto() with the MSG_FASTOPEN flag. This method establishes TCP connections directly through the kernel without invoking the connect() function, thus evading the IP filtering mechanism. The vulnerability is classified as CWE-918 (Server-Side Request Forgery). It allows reaching internal services that should be blocked by the sandbox's banned hosts configuration. The issue was resolved in version 2.8.0 of MaxKB.
Potential Impact
An authenticated user with tool-editing permissions can bypass sandbox network restrictions to access internal services that are explicitly blocked. This could lead to unauthorized internal network access and potential information disclosure or further exploitation within the internal environment. The CVSS v3.1 score of 5.0 reflects a medium impact with low confidentiality, integrity, and availability impacts but requiring low privileges and high attack complexity.
Mitigation Recommendations
This vulnerability has been fixed in MaxKB version 2.8.0. Users should upgrade to version 2.8.0 or later to remediate this issue. Since the product is not a cloud service, remediation requires applying the official patch by updating the software. No other vendor advisory or temporary fixes are provided. 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. The issue arises because the sandbox network protection can be bypassed using the socket. sendto() function with the MSG_FASTOPEN flag, allowing authenticated users with tool-editing permissions to access internal services blocked by the sandbox. This bypass occurs because the sandbox hooks the connect() function to block banned IPs, but sendto() with MSG_FASTOPEN establishes TCP connections without calling connect(), circumventing IP validation. The vulnerability has been fixed in MaxKB version 2. 8. 0. The CVSS score is 5.
CVSS v3.1
Score 5.0medium
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
MaxKB's sandbox network protection relies on hooking the connect() function via LD_PRELOAD to block connections to banned IP addresses. However, in versions 2.7.1 and earlier, an authenticated user with tool-editing permissions can bypass this restriction by using socket.sendto() with the MSG_FASTOPEN flag. This method establishes TCP connections directly through the kernel without invoking the connect() function, thus evading the IP filtering mechanism. The vulnerability is classified as CWE-918 (Server-Side Request Forgery). It allows reaching internal services that should be blocked by the sandbox's banned hosts configuration. The issue was resolved in version 2.8.0 of MaxKB.
Potential Impact
An authenticated user with tool-editing permissions can bypass sandbox network restrictions to access internal services that are explicitly blocked. This could lead to unauthorized internal network access and potential information disclosure or further exploitation within the internal environment. The CVSS v3.1 score of 5.0 reflects a medium impact with low confidentiality, integrity, and availability impacts but requiring low privileges and high attack complexity.
Mitigation Recommendations
This vulnerability has been fixed in MaxKB version 2.8.0. Users should upgrade to version 2.8.0 or later to remediate this issue. Since the product is not a cloud service, remediation requires applying the official patch by updating the software. No other vendor advisory or temporary fixes are provided. 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: 4/21/2026, 6:17:47 AM
Last updated: 5/28/2026, 6:31:02 PM
Views: 42
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