CVE-2026-42336: CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition in 1Panel-dev MaxKB
MaxKB versions 2. 8. 0 and earlier contain a time-of-check to time-of-use (TOCTOU) race condition vulnerability in the OSS file service URL fetch functionality. This flaw allows attackers to bypass server-side request forgery (SSRF) protections by exploiting inconsistent DNS resolution between validation and request execution, potentially enabling access to internal network services. The issue is resolved in version 2. 8. 1. The vulnerability has a medium severity rating with a CVSS 4. 0 base score of 5. 1.
AI Analysis
Technical Summary
CVE-2026-42336 affects MaxKB, an open-source AI assistant for enterprise, in versions prior to 2.8.1. The vulnerability arises from a TOCTOU race condition in the OSS file service URL fetch feature, where DNS resolution differs between the validation phase and the actual request execution. This inconsistency permits attackers to bypass SSRF protections and access internal network resources. The vulnerability is tracked under CWE-367 (TOCTOU Race Condition) and CWE-918 (Server-Side Request Forgery). The issue is fixed in MaxKB version 2.8.1.
Potential Impact
Successful exploitation allows an attacker with limited privileges to bypass SSRF protections and access internal network services that would otherwise be inaccessible. This could lead to unauthorized information disclosure or interaction with internal systems. There are no known exploits in the wild at this time.
Mitigation Recommendations
Upgrade MaxKB to version 2.8.1 or later, where this vulnerability is fixed. Since this is an application-level vulnerability and not a cloud service, applying the official patch is required to remediate the issue. Patch status is confirmed by the vendor stating the fix is included in version 2.8.1.
CVE-2026-42336: CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition in 1Panel-dev MaxKB
Description
MaxKB versions 2. 8. 0 and earlier contain a time-of-check to time-of-use (TOCTOU) race condition vulnerability in the OSS file service URL fetch functionality. This flaw allows attackers to bypass server-side request forgery (SSRF) protections by exploiting inconsistent DNS resolution between validation and request execution, potentially enabling access to internal network services. The issue is resolved in version 2. 8. 1. The vulnerability has a medium severity rating with a CVSS 4. 0 base score of 5. 1.
CVSS v4.0
Score 5.1medium
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-42336 affects MaxKB, an open-source AI assistant for enterprise, in versions prior to 2.8.1. The vulnerability arises from a TOCTOU race condition in the OSS file service URL fetch feature, where DNS resolution differs between the validation phase and the actual request execution. This inconsistency permits attackers to bypass SSRF protections and access internal network resources. The vulnerability is tracked under CWE-367 (TOCTOU Race Condition) and CWE-918 (Server-Side Request Forgery). The issue is fixed in MaxKB version 2.8.1.
Potential Impact
Successful exploitation allows an attacker with limited privileges to bypass SSRF protections and access internal network services that would otherwise be inaccessible. This could lead to unauthorized information disclosure or interaction with internal systems. There are no known exploits in the wild at this time.
Mitigation Recommendations
Upgrade MaxKB to version 2.8.1 or later, where this vulnerability is fixed. Since this is an application-level vulnerability and not a cloud service, applying the official patch is required to remediate the issue. Patch status is confirmed by the vendor stating the fix is included in version 2.8.1.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-26T13:26:14.514Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a16041ae29bf47b505e9f28
Added to database: 5/26/2026, 8:35:38 PM
Last enriched: 5/26/2026, 8:49:57 PM
Last updated: 5/27/2026, 4:55:40 AM
Views: 2
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