CVE-2025-9078: Weak cache keys lead to post IDOR and link preview poisoning

Published Sep 15, 2025
·
Updated

Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.1, 10.9.x <= 10.9.3 fail to properly validate cache keys for link metadata which allows authenticated users to access unauthorized posts and poison link previews via hash collision attacks on FNV-1 hashing

Affected Software

12 affected componentsFixes available
Mattermost Mattermost<=10.8.3, <=10.5.8, <=9.11.17, <=10.10.1, <=10.9.3
Mattermost Mattermost Server>=9.11.0<9.11.18
Mattermost Mattermost Server>=10.5.0<10.5.9
Mattermost Mattermost Server>=10.8.0<10.8.4
Mattermost Mattermost Server>=10.9.0<10.9.4
Mattermost Mattermost Server>=10.10.0<10.10.2
go/github.com/mattermost/mattermost/server/v8<8.0.0-20250718075842-cd87e5c87737
8.0.0-20250718075842-cd87e5c87737
go/github.com/mattermost/mattermost-server>=10.9.0<10.9.4
10.9.4
go/github.com/mattermost/mattermost-server>=10.10.0<10.10.2
10.10.2
go/github.com/mattermost/mattermost-server>=9.11.0<9.11.18
9.11.18
go/github.com/mattermost/mattermost-server>=10.5.0<10.5.9
10.5.9
go/github.com/mattermost/mattermost-server>=10.8.0<10.8.4
10.8.4

Remediation

Information

Update Mattermost to versions 10.11.0, 10.8.4, 10.5.9, 9.11.18, 10.10.2, 10.9.4 or higher.

Event History

Sep 15, 2025
CVE Published
via MITRE·10:10 AM
Data Sourced
via MITRE·10:10 AM
RemedyDescriptionSeverityWeakness
Data Sourced
via NVD·10:15 AM
DescriptionSeverityWeaknessAffected Software
Advisory Published
via GitHub·12:31 PM
Data Sourced
via GitHub·12:31 PM
DescriptionSeverityWeaknessAffected Software
Feb 27, 57989
Event
via FIRST·10:08 PM

Frequently Asked Questions

1

What is the severity of CVE-2025-9078?

CVE-2025-9078 is considered a high-severity vulnerability due to its potential to allow unauthorized access to posts.

2

How do I fix CVE-2025-9078?

To fix CVE-2025-9078, upgrade your Mattermost instance to a version higher than 10.8.3, 10.5.8, 9.11.17, 10.10.1, or 10.9.3.

3

Who is affected by CVE-2025-9078?

CVE-2025-9078 affects Mattermost versions 10.8.x up to 10.8.3, 10.5.x up to 10.5.8, 9.11.x up to 9.11.17, 10.10.x up to 10.10.1, and 10.9.x up to 10.9.3.

4

What types of attacks does CVE-2025-9078 enable?

CVE-2025-9078 enables authenticated users to perform hash collision attacks that could expose unauthorized posts and poison link previews.

5

Is there a workaround for CVE-2025-9078?

Currently, the recommended action for CVE-2025-9078 is to update to a patched version, as no workaround has been specified.

Contact

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