MaxKB: Chat share-link endpoint missing owner check: a chat token can publish another user's conversation

published 2026-09-21 48 d ago modified 2026-09-22 47 d ago also EUVD-2026-84158

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits: 0; none known

MaxKB is an open-source AI assistant for enterprise. In 2.7.0 through 2.10.4-lts, POST /chat/api/{application_id}/chat/{chat_id}/share_chat verifies that a conversation exists but does not verify that it belongs to the authenticated chat_user_id or to the application bound to the caller's token. An attacker with any chat token and a known victim chat_id can create an unauthenticated public ChatShareLink exposing the victim's conversation and can create PublicFileAccess state that makes associated files retrievable without credentials, with no available revoke path. No fixed version is available as of this review.

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 47 d ago (2026-09-22)

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

Affected products

1Panel-dev MaxKB

Classification

Weakness

CWE-285 Improper Authorization
CWE-639 Authorization Bypass Through User-Controlled Key

References

github.com /1Panel-dev/MaxKB/security/advisories/GHSA-m8gr-554p-8r82

Sources

CVE List CVE-2026-79917
NVD CVE-2026-79917

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.

Summary