Is there a patch available for CVE-2026-42335?

Yes, a patch is available for CVE-2026-42335. Update the affected software to the latest version immediately.

MaxKB CVE-2026-42335

Q: What is the CVSS score of CVE-2026-42335?

CVE-2026-42335 has a CVSS 4.0 base score of 6.3 (Medium). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

EUVD-2026-31983 MEDIUM

Server-Side Request Forgery (SSRF) (CWE-918)

2026-05-26 GitHub_M

SSRF Maxkb

6.3

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

6.3 MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Lifecycle Timeline

Patch available

May 26, 2026 - 22:02 EUVD

Analysis Generated

May 26, 2026 - 21:34 vuln.today

CVSS changed

May 26, 2026 - 21:22 NVD

6.3 (MEDIUM)

CVE Published

May 26, 2026 - 20:09 nvd

UNKNOWN (no severity yet)

DescriptionGitHub Advisory

MaxKB is an open-source AI assistant for enterprise. Prior to 2.8.1, MaxKB v2.8.0 and prior are vulnerable to a server-side request forgery (SSRF) bypass in the OSS file service URL fetch (chat/api/oss/get_url) endpoint. The vulnerability exists due to inconsistent URL parsing between the urlparse validation function and the requests HTTP client, allowing attackers to access internal network services. This vulnerability is fixed in 2.8.1.

AnalysisAI

Server-side request forgery in MaxKB v2.8.0 and earlier allows authenticated low-privilege users to reach internal network services by exploiting an URL parsing inconsistency at the OSS file fetch endpoint. The discrepancy between Python's urlparse validation logic and the requests HTTP client means a crafted URL can pass security checks yet still route to internal infrastructure when executed by the server. No public exploit or KEV listing exists at time of analysis; the vendor has confirmed and patched the issue in 2.8.1.

Technical ContextAI

MaxKB is an open-source enterprise AI knowledge-base assistant maintained by 1Panel-dev (CPE: cpe:2.3:a:1panel-dev:maxkb:*:*:*:*:*:*:*:*). The vulnerable endpoint, chat/api/oss/get_url, is part of the Object Storage Service (OSS) file-service layer designed to fetch remote URLs on behalf of the application. The root cause (CWE-918) is an SSRF arising from differential URL parsing: the application validates input URLs with Python's urlparse, but the actual HTTP request is issued by the requests library. These two parsers handle edge cases - such as malformed schemes, embedded credentials, or unusual IP representations - differently, creating a gap an attacker can exploit to submit a URL that appears safe to the validator but resolves to an internal address when fetched. This class of parsing discrepancy is well-documented in SSRF research and commonly affects Python web stacks that separate validation from execution across library boundaries.

RemediationAI

Upgrade MaxKB to version 2.8.1, which contains the vendor-confirmed fix. The advisory is available at https://github.com/1Panel-dev/MaxKB/security/advisories/GHSA-r8hf-mwwr-hxgc. If immediate upgrade is not feasible, restrict access to the chat/api/oss/get_url endpoint at the reverse-proxy or WAF layer to trusted users or IP ranges only - note this may break legitimate OSS URL fetch workflows. Alternatively, apply network egress controls on the MaxKB host to prevent outbound connections to internal RFC-1918 address ranges, link-local addresses (169.254.x.x), and loopback; this limits SSRF blast radius without touching the application but adds operational overhead for managing egress rules. If cloud-hosted, prioritize blocking access to the instance metadata service endpoint as a compensating control.