synced 4 MIN AGO
01 Record

CVE-2018-21257

An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended access restrictions (for setting a channel header) via the Channel header slash command API.

UnratedPUBLISHEDCNA: mitre
CNA base scoreUnratedNo CNA CVSS vector

02 Description

An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended access restrictions (for setting a channel header) via the Channel header slash command API.

03 Exploitation and scoring

Exploitation
Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision
Not assessed by CISA
EPSS probability
0.81% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 56.6% of scored records. A rank, not a probability.
NVD base score
5.3 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2020-06-19 16:51Z6 YR AGO
Last updated
2024-08-05 12:26Z2 YR AGO
Reserved
2020-06-19
Assigning CNA
mitre
Record state
PUBLISHED
Severity
Not rated by the issuing CNA
CNA CVSS vector
Not published by the issuing CNA
Weaknesses
Data version
5.1
Document digest
180a315f3428f6984143e1bdb47bc0f84605a8b2fa1066c25a4749e418da14e1

05 Affected products

VendorProductVersionsPlatforms
mattermostmattermost_serverNot specified—

06 References