GHSA-4fwj-8595-wp25 CVE-2025-6227 GO-2025-3818

Mattermost has Insufficiently Protected Credentials

Low Go

Severity: 2.2 / 10; Low · CVSS 3.1
Exploit chance (EPSS): 0.22%; Chance of exploitation in the next 30 days. Higher than 12.04% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-522 Insufficiently Protected Credentials
Fix: Available; 2 packages have a fixed version

Description

Mattermost versions 10.5.x <= 10.5.7, 9.11.x <= 9.11.16 fail to negotiate a new token when accepting the invite which allows a user that intercepts both invite and password to send synchronization payloads to the server that originally created the invite via the REST API.

Affected versions

Go

Package	Vulnerable	Fixed in
github.com/mattermost/mattermost-server	`>= 10.5.0, < 10.5.8`	`10.5.8`
github.com/mattermost/mattermost-server	`>= 9.11.0, < 9.11.17`	`9.11.17`
github.com/mattermost/mattermost-server	`>= 9.11.0+incompatible, < 9.11.17+incompatible` `>= 10.5.0+incompatible, < 10.5.8+incompatible`	`9.11.17+incompatible` `10.5.8+incompatible`
github.com/mattermost/mattermost-server/v5	`all versions`	No fix yet
github.com/mattermost/mattermost-server/v6	`all versions`	No fix yet
github.com/mattermost/mattermost/server/v8	`< 8.0.0-20250612074655-8f8612c63783`	`8.0.0-20250612074655-8f8612c63783`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

github.com/mattermost/mattermost-server Go → `10.5.8`

go

go get github.com/mattermost/mattermost-server@v10.5.8 && go mod tidy

github.com/mattermost/mattermost/server/v8 Go → `8.0.0-20250612074655-8f8612c63783`

go

go get github.com/mattermost/mattermost/server/v8@v8.0.0-20250612074655-8f8612c63783 && go mod tidy

Severity breakdown

CVSS 3.1 2.2

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

Attack vector: Network
Attack complexity: High
Privileges required: High
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Weakness

CWE-522: Insufficiently Protected Credentials

The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.

How to prevent it

Architecture and Design: Use an appropriate security mechanism to protect the credentials.
Architecture and Design: Make appropriate use of cryptography to protect the credentials.
Implementation: Use industry standards to protect the credentials (e.g. LDAP, keystore, etc.).

References

Advisories

Packages

github.com/mattermost/mattermost

Timeline

Jul 18, 2025 Published
Jun 17, 2026 Last updated by the source
Nov 1, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-xmfh-3ccg-c9fx Mattermost has an Incorrect Authorization issue	Low	Also affects github.com/mattermost/mattermost-server
GHSA-h998-hxxj-8q83 Mattermost doesn't invalidate cached authentication state for active WebSocket connections during global session revocation	Medium	Also affects github.com/mattermost/mattermost-server
GHSA-g5vr-6pgg-74qv Mattermost doesn't enforce bot-specific permission checks on the user active status endpoint	Low	Also affects github.com/mattermost/mattermost-server
GHSA-jqgv-39mg-7c2r Mattermost doesn't authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret	Medium	Also affects github.com/mattermost/mattermost-server
GHSA-mxq2-5jpg-7474 Mattermost doesn't validate channel ownership of an existing subscription before applying edits	Medium	Also affects github.com/mattermost/mattermost-server
GHSA-2g8v-grq3-hq2g Mattermost doesn't enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler	Medium	Also affects github.com/mattermost/mattermost-server
GHSA-6hxm-w4hv-vgvw Mattermost doesn't require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints	High	Also affects github.com/mattermost/mattermost-server
GHSA-9p44-r552-4wp9 Mattermost doesn't sanitize the Remote Cluster API response on PATCH operations	Medium	Also affects github.com/mattermost/mattermost-server

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