CVE-2026-27656

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

• ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.18% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 7.7% of scored records. A rank, not a probability.

NVD base score

6.1 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Analyzed. 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.

Published

2026-03-25 16:28Z5 MO AGO

Last updated

2026-03-26 13:19Z5 MO AGO

Reserved

2026-02-23

Assigning CNA

Mattermost

Record state

PUBLISHED

Severity

Medium (CVSS 5.7)

CNA CVSS vector

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

Weaknesses

• CWE-303Incorrect Implementation of Authentication AlgorithmBase

Data version

5.2

Document digest

54c569131e15bba93b851d1db223f9dd6440ce0383a25ee810affe6786f55916

• mattermost.comMMSA-2026-00590https://mattermost.com/security-updatesvendor-advisory