CVE-2018-21251

An issue was discovered in Mattermost Server before 5.2 and 5.1.1. Authorization could be bypassed if the channel name were not the same in the params and the body.

CVSS 9.8 · Critical

External lookup

Potential internet exposure

Potential exposure only — not proof of vulnerability.Shodan results indicate potentially internet-exposed products, not confirmed vulnerable systems. They do not confirm that any returned system is vulnerable to CVE-2018-21251.

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Product CPE queries

Derived from this CVE's existing NVD CPE 2.3 records; the application, operating-system, or hardware part is retained.

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Exact CVE query

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Metadata

Canonical fields

NVD status

Unavailable

Published

Jun 19, 2020

Modified

Jun 17, 2026

Official record

Authoritative NVD record

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE IDs

Vendor classifications

How this vector reads

CVSS 3.1 base metrics decoded below. This explanation does not recalculate or change the NVD score.

Attack Vector (AV): Network. The vulnerable system can be reached across network boundaries.
Attack Complexity (AC): Low. No special conditions beyond the attacker-controlled steps are required.
Privileges Required (PR): None. The attacker needs no privileges on the vulnerable system.
User Interaction (UI): None. Exploitation does not require another user to act.
Scope (S): Unchanged. Impacts remain within the vulnerable security authority.
Confidentiality Impact (C): High. There is a total or serious impact to this security property.
Integrity Impact (I): High. There is a total or serious impact to this security property.
Availability Impact (A): High. There is a total or serious impact to this security property.

Signals

Exploitation indicators

0 stored signals · no KEV · 0 OTX pulses