Is CVE-2026-4400 actively exploited?

No active exploitation of CVE-2026-4400 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-4400 be exploited remotely?

Yes. CVE-2026-4400 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-4400?

CVE-2026-4400 has a CVSS score of 7.0 (HIGH).

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HIGH

CVE-2026-4400

CWE-639Published: March 31, 2026· Updated: Apr 1, 2026

7.0

CVSS v3.1

EPSS:0.19%probability of exploitation in 30 daysPercentile:41.3th

Official Description

Insecure Direct Object Reference (IDOR) vulnerability in 1millionbot Millie chat that allows private conversations of other users being viewed by simply changing the conversation ID. The vulnerability is present in the endpoint 'api.1millionbot.com/api/public/conversations/' and, if exploited, could allow a remote attacker to access other users private chatbot conversations, revealing sensitive or confidential data without requiring credentials or impersonating users. In order for the vulnerability to be exploited, the attacker must have the user's conversation ID.

NVD Source

Technical Analysis

CVE-2026-4400 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges Req.None

User InteractionNone

ScopeX

Impact

Confidentiality

Integrity

Availability

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/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