MaxKB: SSRF Bypass via DNS Rebinding in MaxKB OSS URL Fetch

published 2026-05-26 5 mo ago modified 2026-07-23 3 mo ago also EUVD-2026-31989

cvss: 5.1; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 10%
public exploits: 0; none known

MaxKB is an open-source AI assistant for enterprise. MaxKB 2.8.0 and prior are vulnerable to a server-side request forgery (SSRF) bypass in the OSS file service URL fetch functionality due to inconsistent DNS resolution between validation and actual request execution, allowing attackers to access internal network services. This vulnerability is fixed in 2.8.1.

Patch / fix

fixed in 1

maxkb maxkb 2.8.1

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 5 mo ago (2026-05-27)

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.1	CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N
CNA	4.0	5.1	CVSS:4.0/AV:N/AC:H/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

Affected products

1Panel-dev MaxKB

Classification

Weakness

CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
CWE-918 Server-Side Request Forgery

References

github.com /1Panel-dev/MaxKB/security/advisories/GHSA-6m4p-9wwc-4q5q

Sources

CVE List CVE-2026-42336
NVD CVE-2026-42336

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary