Mattermost third-party support
Mattermost 11.10
Mattermost 11.10
The Mattermost 11.10 reaches end of service life on Nov 15, 2026. Third-party support keeps it managed past that date — issue management, vulnerability remediation, and compliance maintenance from 24/7 engineers.
EOSL ApproachingEOSL Date: Nov 15, 2026
Issue Management
24/7 engineers own your Mattermost 11.10 incidents end to end.
Vulnerability Remediation
Mitigation and patch-around guidance when the vendor no longer ships fixes.
Compliance Maintenance
Controls evidence and documentation that keep auditors satisfied.
Specifications
- product
- mattermost
- release
- 11.10
- product Label
- Mattermost
- release Label
- 11.10
- codename
- lts
- latest Version
- 11.10.5
- release Date
- 2026-08-14
- maintained
- true
- source Url
- https://endoflife.date/mattermost
Lifecycle Dates
- End of Service Life
- Nov 15, 2026
- Last OEM Support
- Nov 15, 2026
OEM vs. 3rd Party Support
See how third-party support compares to the vendor contract for Mattermost 11.10 — 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 11.10?
Vulnerability Remediation
Scanning, mitigation and patch-around guidance for Mattermost 11.10 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 11.10 Support: Frequently Asked Questions
Is the Mattermost 11.10 still supported?
Yes, but Mattermost support for the Mattermost 11.10 ends on Nov 15, 2026. You can upgrade on the vendor's schedule, or move to third-party support and keep the release you're on — issues managed, vulnerabilities remediated, compliance maintained.
When is the Mattermost 11.10 end of service life (EOSL) date?
Mattermost lists the end of service life for the Mattermost 11.10 as Nov 15, 2026.
Can I keep using the Mattermost 11.10 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 11.10 cost?
Typically 40-70% below the OEM maintenance renewal price. Exact pricing depends on quantity, service level and location. You get an indicative price within 24 hours and a firm quote within 48.
Known Vulnerabilities Affecting Mattermost 11.10
20 published CVEs affect the Mattermost 11.10, including 1 rated critical or high severity. Our 24/7 engineers help you assess exposure, prioritize fixes and apply available patches.
| CVE | Severity | CVSS | Published | Summary |
|---|---|---|---|---|
| CVE-2026-16453 | HIGH | 7.1 | Oct 16, 2026 | Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to verify the integrity of the SAML RelayState POST parameter which allows an authenticated SAML user to join any team, including invite-only teams, via forging the team_id or invite_id fields in the RelayState.. Mattermost Advisory ID: MMSA-2026-00727 |
| CVE-2026-93850 | MEDIUM | 6.5 | Oct 26, 2026 | Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to bind the volume of text extracted from an uploaded PDF which allows an authenticated user to exhaust server memory and cause a denial of service via a crafted PDF whose compressed content stream expands into a very large amount of text.. Mattermost Advisory ID: MMSA-2026-00769 |
| CVE-2026-93849 | MEDIUM | 6.5 | Oct 26, 2026 | Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 Mattermost fail to apply allocation limits to the byte-string decode paths in its WebSocket msgpack decoder, which allows an authenticated remote attacker to cause excessive server memory allocation via a crafted binary WebSocket frame declaring a Bin32 payload length of up to 4,294,967,295 bytes.. Mattermost Advisory ID: MMSA-2026-00768 |
| CVE-2026-19621 | MEDIUM | 6.5 | Oct 16, 2026 | Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to strip action integration secrets from post payloads before broadcasting post-deletion web socket events and returning thread API responses, which allows an authenticated channel member to obtain server-side webhook URLs and authentication context from interactive-message posts via the post_deleted websocket event or the threads REST API.. Mattermost Advisory ID: MMSA-2026-00766 |
| CVE-2026-16251 | MEDIUM | 6.5 | Oct 16, 2026 | Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to limit the size of remote image responses buffered in memory during local image proxy direct fetches, which allows a remote attacker to cause memory exhaustion on the server via a crafted oversized image response.. Mattermost Advisory ID: MMSA-2026-00726 |
| CVE-2026-19541 | MEDIUM | 6.5 | Oct 16, 2026 | Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to require re-entry of the stored client secret when validating an outgoing OAuth connection, which allows an authenticated user with permission to manage outgoing OAuth connections to obtain the secret via pointing the token URL at an attacker-controlled endpoint and triggering validation.. Mattermost Advisory ID: MMSA-2026-00761 |
| CVE-2026-18551 | MEDIUM | 6.5 | Oct 16, 2026 | Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to validate the combination of guest and admin scheme roles which allows an authenticated attacker to escalate a guest account to team or channel admin via a crafted PUT request to the member roles API endpoint.. Mattermost Advisory ID: MMSA-2026-00752 |
| CVE-2026-96260 | MEDIUM | 6.5 | Sep 22, 2026 | Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to enforce a request body size limit during CSRF validation of plugin requests which allows an authenticated user to exhaust server memory and cause a denial of service via a large request body sent to a plugin endpoint.. Mattermost Advisory ID: MMSA-2026-00775 |
| CVE-2026-18795 | MEDIUM | 6.4 | Oct 16, 2026 | Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756 |
| CVE-2026-96259 | MEDIUM | 5.5 | Sep 22, 2026 | Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to apply the internal-connection filter to OAuth endpoint requests, which allows a System Administrator to make the server issue requests to internal network addresses and read the responses via the configured OAuth token and userinfo endpoints.. Mattermost Advisory ID: MMSA-2026-00776 |
| CVE-2026-18223 | MEDIUM | 5.0 | Oct 16, 2026 | Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to validate the invited recipient's email address when redeeming team and guest invitation tokens, which allows an authenticated attacker to join a team or gain unauthorized access to private channels via a forwarded or leaked invitation link.. Mattermost Advisory ID: MMSA-2026-00747 |
| CVE-2026-19601 | MEDIUM | 4.9 | Oct 16, 2026 | Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to invalidate the stored AD/LDAP bind password when other connection settings (such as the server address) are changed, which allows a System Console administrator to disclose the plaintext bind password to an attacker-controlled server via the Test Connection / diagnostics feature. Mattermost Advisory ID: MMSA-2026-00764 |
| CVE-2026-19600 | MEDIUM | 4.5 | Oct 16, 2026 | Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to sanitize authentication tokens before writing them to server log entries, which allows an attacker with access to server logs to obtain valid session tokens or OAuth access tokens and impersonate authenticated users via the debug-level Mattermost server log.. Mattermost Advisory ID: MMSA-2026-00763 |
| CVE-2026-19076 | MEDIUM | 4.4 | Oct 16, 2026 | Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to reject OAuth application sessions in the account type switch endpoint, which allows an attacker with a valid OAuth bearer token for a target user to permanently take over that user's SSO-backed account by setting an attacker-controlled password and detaching the account from its identity provider via a crafted request to POST /api/v4/users/login/switch.. Mattermost Advisory ID: MMSA-2026-00758 |
| CVE-2026-18799 | MEDIUM | 4.3 | Oct 16, 2026 | Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to restrict Slack import account binding to system administrator-initiated imports which allows an authenticated attacker with team admin privileges to force-add existing Mattermost users to their team and forge posts attributed to those users' identities via a crafted Slack export containing target users' email addresses.. Mattermost Advisory ID: MMSA-2026-00757 |
| CVE-2026-18560 | MEDIUM | 4.3 | Oct 16, 2026 | Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to validate user’s permissions before other validations which allows non-content reviewers to infer a post’s flagged status via direct API call.. Mattermost Advisory ID: MMSA-2026-00754 |
| CVE-2026-18256 | MEDIUM | 4.3 | Oct 16, 2026 | Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to properly restrict private teams from public team search results, which allows an authenticated user without permission to list private teams to disclose the ID, name, and display name of private teams via a modified team search request. Mattermost Advisory ID: MMSA-2026-00748 |
| CVE-2026-19867 | MEDIUM | 4.3 | Oct 16, 2026 | Mattermost versions 11.10.x <= 11.10.0, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10 fail to cap the number and size of mention keys stored in a user's notification properties, and to bound the quadratic multibyte-keyword matching performed for each post, which allows an authenticated user to degrade post-processing latency and consume excessive CPU on behalf of other members of any channel they share via storing an oversized notify_props.mention_keys list on their own profile.. Matterm |
| CVE-2026-19603 | MEDIUM | 4.3 | Oct 16, 2026 | Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to sanitize the active channel field returned by the user status API endpoints, which allows an authenticated user to learn the channel ID of a private channel another user is actively viewing via the status endpoints, without being a member of that channel. Mattermost Advisory ID: MMSA-2026-00765 |
| CVE-2026-95666 | MEDIUM | 4.3 | Sep 22, 2026 | Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to limit the length of the post ID array accepted by the bulk reactions endpoint which allows an authenticated user to cause excessive database load via a crafted request to {{POST /api/v4/posts/ids/reactions}}.. Mattermost Advisory ID: MMSA-2026-00771 |
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