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  4. CVE 2026 6739 mattermost doesnt require system level permission
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Back to active CVEs
Medium · CVSS 6.7CVE-2026-6739GHSA-M2W9-H2MM-79QR

Mattermost doesn't require system-level permission when patching protected default system rolesCVE-2026-6739

Answer in brief

CVE-2026-6739 records a Medium severity (CVSS 6.7) vulnerability in Mattermost doesn't require system-level permission when patching protected default system roles. The current sources do not mark it as known exploited. The current feed maps github.com/mattermost/mattermost-server (go), github.com/mattermost/mattermost-server (go), github.com/mattermost/mattermost-server (go), github.com/mattermost/mattermost-server (go) and additional mapped packages. Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jun 12, 2026Updated Sep 10, 2026Source checked Oct 10, 2026First seen by HOL Aug 25, 2026Material review Sep 10, 2026
Upstream Advisory

Key facts

Risk
Medium · CVSS 6.7
Exploitation
Not marked as known exploited
Affected software
8 mapped packages or products
Fix availability
Available

Why this deserves its current priority

CVSS is 6.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps github.com/mattermost/mattermost-server (go), github.com/mattermost/mattermost-server (go), github.com/mattermost/mattermost-server (go), github.com/mattermost/mattermost-server (go) and additional mapped packages. Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
github.com/mattermost/mattermost-servergo=11.6.011.6.1
github.com/mattermost/mattermost-servergo>=11.5.0,<=11.5.411.5.5
github.com/mattermost/mattermost-servergo>=10.11.0,<=10.11.1510.11.17
github.com/mattermost/mattermost-servergo>=11.6.0 <11.6.111.6.1
github.com/mattermost/mattermost-servergo>=11.5.0 <11.5.511.5.5
github.com/mattermost/mattermost-servergo>=10.11.0 <10.11.1710.11.17
github.com/mattermost/mattermost/server/v8go>=8.0.0-20250731163400-5b955468ea1e,<8.0.0-20260501142004-99b73d4c4acf8.0.0-20260501142004-99b73d4c4acf
github.com/mattermost/mattermost/server/v8go>=8.0.0-20250731163400-5b955468ea1e <8.0.0-20260501142004-99b73d4c4acf8.0.0-20260501142004-99b73d4c4acf

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for github.com/mattermost/mattermost-server, github.com/mattermost/mattermost-server, github.com/mattermost/mattermost-server.
  2. 2Review the reported fix. Update github.com/mattermost/mattermost-server to 11.6.1; github.com/mattermost/mattermost-server to 11.5.5; github.com/mattermost/mattermost-server to 10.11.17; github.com/mattermost/mattermost-server to 11.6.1; github.com/mattermost/mattermost-server to 11.5.5; github.com/mattermost/mattermost-server to 10.11.17; github.com/mattermost/mattermost/server/v8 to 8.0.0-20260501142004-99b73d4c4acf; github.com/mattermost/mattermost/server/v8 to 8.0.0-20260501142004-99b73d4c4acf if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Jun 12, 2026

    Evidence: source:ghsa:source_dates:source-dates:record

  2. Source modified

    Sep 10, 2026

    Evidence: source:ghsa:source_dates:source-dates:record

  3. First seen by HOL

    Aug 25, 2026

Sources and claim methodology

  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • Source referencemattermost.com
  • NVD vulnerability recordnvd.nist.gov
  • GitHub security advisorygithub.com
Upstream source description

Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-in role permissions via the role patch API. Mattermost Advisory ID: MMSA-2026-00656

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • OWASP Coraza WAF: ProcessURI silently drops QUERY_STRING and ARGS_GET on URI parse failure — defense-in-depth bypass for non-net/http integrationsSame go ecosystem
  • OWASP Coraza WAF: JSON body processor: argument-limit truncation reopens an unbounded-depth gjson.Valid stack overflow (process crash)Same go ecosystem
  • OWASP Coraza WAF: Unbounded recursion in JSON response body processor causes CPU exhaustionSame go ecosystem
  • OWASP Coraza WAF: Resource exhaustion via deferred file handle accumulation in multipart body processorSame go ecosystem
  • ageLANServer: Unbounded JSON Array Allocation in AoE3 Cloud `getFileURL` Endpoint Leads to Remote Denial of ServiceSame go ecosystem
  • yopass Prometheus metrics middleware allows remote memory exhaustion through unbounded method labelsSame go ecosystem

Record context

Vulnerability class
Vulnerability
EPSS
Not reported
CWE IDs
Not reported
Source
GitHub Security Advisories
Source checked
Oct 10, 2026
References
17 linked sources
Open source record