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Back to active CVEs
Medium · CVSS 5.4CVE-2026-16044

Insufficient validation of guest board admin privileges on archive import

Answer in brief

CVE-2026-16044 records a Medium severity (CVSS 5.4) vulnerability in Insufficient validation of guest board admin privileges on archive import. The current sources do not mark it as known exploited. The current feed maps Mattermost/Mattermost (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

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

Published Aug 17, 2026Updated Aug 18, 2026Source checked Oct 1, 2026First seen by HOL Aug 17, 2026Material review Aug 18, 2026
Upstream Advisory

Key facts

Risk
Medium · CVSS 5.4
Exploitation
Not marked as known exploited
Affected software
2 mapped packages or products
Fix availability
Not reported

Why this deserves its current priority

CVSS is 5.4. 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 Mattermost/Mattermost (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
ProductAffected versionsFixed versions
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*Not reportedNot reported
Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Mattermost/Mattermostgeneric11.7.0 || 10.11.0Not reported

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Mattermost/Mattermost.
  2. 2Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

  1. Published upstream

    Aug 17, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Aug 18, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Aug 17, 2026

Sources and claim methodology

  • Source referencemattermost.com
Upstream source description

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive import which allows a board member to escalate a guest user to Board Admin via importing a crafted .boardarchive file. Mattermost Advisory ID: MMSA-2026-00672

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • RT-Labs AB C-Open CANopen SDO Server Write Protection BypassAlso CWE-863
  • Office-PowerPoint-MCP-Server through 2.0.7 Path Traversal via save_presentation and manage_imageSame generic ecosystem
  • Wormhole.app SSRFSame generic ecosystem
  • Physical UART Access Leading to an Unauthenticated Root Shell in TP-Link Kasa EC70 and EC71Same generic ecosystem
  • Out-of-bounds write in PeaZip PEA extractor allows code execution via a crafted .pea archiveSame generic ecosystem
  • Cadmos LTI exposure of sensitive information via debug modeSame generic ecosystem

Record context

Vulnerability class
Vulnerability
EPSS
Not reported
CWE IDs
CWE-863
Source
CVE List V5
Source checked
Oct 1, 2026
References
1 linked source
Open source record