Mattermost 9.8
Mattermost 9.8
The Mattermost 9.8 reached end of service life on Aug 15, 2024 — Mattermost no longer ships security patches or fixes for it. Our third-party support keeps it safe to run: 24/7 engineers manage issues, remediate vulnerabilities, and help you maintain compliance.
24/7 engineers own your Mattermost 9.8 incidents end to end.
Mitigation and patch-around guidance when the vendor no longer ships fixes.
Controls evidence and documentation that keep auditors satisfied.
Specifications
- product
- mattermost
- release
- 9.8
- product Label
- Mattermost
- release Label
- 9.8
- codename
- lts
- latest Version
- 9.8.3
- release Date
- 2024-05-03
- maintained
- source Url
- https://endoflife.date/mattermost
Lifecycle Dates
- End of Service Life
- Aug 15, 2024
- Last OEM Support
- Aug 15, 2024
OEM vs. 3rd Party Support
See how third-party support compares to the vendor contract for Mattermost 9.8 — monitoring, break/fix, vulnerability work, operations and compliance, before and after EOSL.
| Feature | OEM Support | 3rd Party Support |
|---|---|---|
| Post-EOSL Support | ||
| Break/Fix Support | Until EOSL | |
| 24/7 Monitoring | ||
| Vulnerability Scanning & Remediation | ||
| Managed Operations | ||
| Procedure & Configuration Review | ||
| Compliance & Audit Documentation | Limited | |
| Discounted Migration to Other Platforms |
Why Choose 3rd Party Support for Mattermost 9.8?
Vulnerability Remediation
Scanning, mitigation and patch-around guidance for Mattermost 9.8 when the vendor no longer ships fixes.
Compliance Maintenance
Procedure review, controls evidence and the documentation auditors ask for — maintained continuously, not scrambled at audit time.
24/7 Expert Support
Engineers who know this release monitor, manage and fix issues around the clock — break/fix to managed operations.
Mattermost 9.8 Support: Frequently Asked Questions
Is the Mattermost 9.8 still supported?
Mattermost ended support for the Mattermost 9.8 on Aug 15, 2024 — no more patches or fixes from the vendor. Third-party support keeps it covered: our engineers manage issues, remediate vulnerabilities, and help you maintain compliance for as long as you run it.
When is the Mattermost 9.8 end of service life (EOSL) date?
Mattermost lists the end of service life for the Mattermost 9.8 as Aug 15, 2024.
Can I keep using the Mattermost 9.8 after its EOSL date?
Yes. EOSL means Mattermost stops issuing patches and support — the software itself keeps running. Third-party support covers it from there: issue management, security vulnerability remediation, and the compliance documentation auditors ask for, for as long as you choose to run it.
How much does third-party support for the Mattermost 9.8 cost?
Typically 40-70% below the OEM maintenance renewal price. Exact pricing depends on quantity, service level and location — request a quote and we respond within 24 hours.
Known Vulnerabilities Affecting Mattermost 9.8
11 published CVEs affect the Mattermost 9.8. Mattermost no longer ships security patches for this release — our engineers provide mitigation guidance, workarounds and hardening support.
| CVE | Severity | CVSS | Published | Summary |
|---|---|---|---|---|
| CVE-2025-55070 | MEDIUM | 6.5 | Nov 14, 2025 | Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events |
| CVE-2024-42497 | MEDIUM | 6.0 | Aug 22, 2024 | Mattermost versions 9.9.x <= 9.9.1, 9.5.x <= 9.5.7, 9.10.x <= 9.10.0, 9.8.x <= 9.8.2 fail to properly enforce permissions which allows a user with systems manager role with read-only access to teams to perform write operations on teams. |
| CVE-2024-41144 | MEDIUM | 5.5 | Aug 1, 2024 | Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to properly validate synced posts, when shared channels are enabled, which allows a malicious remote to create/update/delete arbitrary posts in arbitrary channels |
| CVE-2025-27936 | MEDIUM | 5.3 | Apr 16, 2025 | Mattermost Plugin MSTeams versions <2.1.0 and Mattermost Server versions 10.5.x <=10.5.1 with the MS Teams plugin enabled fail to perform constant time comparison on a MSTeams plugin webhook secret which allows an attacker to retrieve the webhook secret of the MSTeams plugin via a timing attack during webhook secret comparison. |
| CVE-2024-12247 | MEDIUM | 4.6 | Dec 5, 2024 | Mattermost versions 9.7.x <= 9.7.5, 9.8.x <= 9.8.2 and 9.9.x <= 9.9.2 fail to properly propagate permission scheme updates across cluster nodes which allows a user to keep old permissions, even if the permission scheme has been updated. |
| CVE-2026-2461 | MEDIUM | 4.3 | Mar 16, 2026 | Mattermost Plugins versions <=11.3 11.0.3 11.2.2 10.10.11.0 fail to implement authorisation checks on comment block modifications, which allows an authorised attacker with editor permission to modify comments created by other board members. Mattermost Advisory ID: MMSA-2025-00559 |
| CVE-2025-11776 | MEDIUM | 4.3 | Nov 14, 2025 | 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 |
| CVE-2024-43780 | MEDIUM | 4.3 | Aug 22, 2024 | Mattermost versions 9.9.x <= 9.9.1, 9.5.x <= 9.5.7, 9.10.0, 9.8.x <= 9.8.2 fail to enforce permissions which allows a guest user with read access to upload files to a channel. |
| CVE-2024-39839 | MEDIUM | 4.3 | Aug 1, 2024 | Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to disallow users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary string, which would be then synced to the local server as long as the user hadn't been synced before. |
| CVE-2024-41162 | MEDIUM | 4.1 | Aug 1, 2024 | Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5 and 9.8.x <= 9.8.1 fail to disallow the modification of local channels by a remote, when shared channels are enabled, which allows a malicious remote to make an arbitrary local channel read-only. |
| CVE-2025-41436 | LOW | 3.1 | Nov 14, 2025 | Mattermost versions <11.0 fail to properly enforce the "Allow users to view archived channels" setting which allows regular users to access archived channel content and files via the "Open in Channel" functionality from followed threads |