CVE-2025-11776

Guest user can discover archived public channels

MEDIUM

4.3

CVSS Score

Published: November 14, 2025 at 07:58 AM UTC

Updated: October 19, 2026 at 01:10 PM UTC

2 products affected across 1 vendorMattermost ServerMattermost

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Severity

MEDIUM4.3

Exploit prediction

EPSS 0.2%

SSVC

No known exploit

Description

Mattermost versions <11 fail to properly restrict access to archived channel search API which allows guest users to discover archived public channels via the `/api/v4/teams/{team_id}/channels/search_archived` endpoint

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Mattermost Server · Mattermost

95%

v < 11.0.0

Mattermost · Mattermost

90%

v ≤ <11<11

Vendor states this is fixed in 11.0.0 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://mattermost.com/security-updates

References (1)

Vendor Advisory

Source: cverecord

https://mattermost.com/security-updates

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMMattermost

Attack Vector: NETWORK
Complexity: LOW
Privileges: LOW
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: LOW
Integrity: NONE
Availability: NONE

Vector?

Quick Info

StatusANALYZED

CWE

CWE-863

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