Is CVE-2026-6046 in the CISA KEV catalog?

No. CVE-2026-6046 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-6046?

CVE-2026-6046 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-6046?

CVE-2026-6046 has an EPSS score of 0.19% (9th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-6046?

Upgrade mattermost server to 11.6.2 or later.

CVE & CISA-KEV Catalog

CVE-2026-6046

MEDIUM

5.3

CVSS v3

NVD

Description

Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to validate that a username returned during bot registration belongs to a bot account, which allows an unprivileged attacker to intercept private messages sent by plugins via direct message channels by pre-registering a user account with a predictable plugin bot username.. Mattermost Advisory ID: MMSA-2026-00649

CWE-200Information Exposure

How to fix

Remediation Available

mattermost serverNVD

Affected:>= 11.6.0, < 11.6.2Fixed in:11.6.2CVE-2026-6046derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

0.19%probability of exploitation in 30 days

9thpercentile

Low risk: more likely to be exploited than 9% of all known CVEs.

References

Vendor Advisory1

mattermost.com

Related Vulnerabilities

Other CWE-200 (Information Exposure) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-24919	High	8.6	100%	KEV + Ransom	-
CVE-2020-14181	Medium	5.3	100%	-	Fix
CVE-2021-34429	Medium	5.3	99%	-	Fix
CVE-2018-11409	Medium	5.3	98%	-	-
CVE-2021-41277	Critical	10.0	97%	KEV	-
CVE-2016-2183	High	7.5	96%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-18.