Boards archive import endpoint allows resource exhaustion via zip bomb and file size limit bypass in Mattermost (CVE-2026-14298) | HOL Guard CVE

Medium · CVSS 6.5CVE-2026-14298

Boards archive import endpoint allows resource exhaustion via zip bomb and file size limit bypass in Mattermost

Answer in brief

CVE-2026-14298 records a Medium severity (CVSS 6.5) vulnerability in Boards archive import endpoint allows resource exhaustion via zip bomb and file size limit bypass in Mattermost. 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 13, 2026Updated Sep 14, 2026Source checked Sep 14, 2026First seen by HOL Aug 13, 2026Material review Sep 14, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.5
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 6.5. 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
Product	Affected versions	Fixed versions
cpe:2.3:a:mattermost:mattermost_server::::::::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Mattermost/Mattermostgeneric	11.9.0 \|\| 11.8.0 \|\| 11.7.0 \|\| 10.11.0	Not reported

Recommended response

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

Evidence timeline and material changes

Published upstream
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 13, 2026

Sources and claim methodology

Source referencemattermost.com

Upstream source description

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to limit decompressed content size and enforce the configured maximum file size in the Boards archive import handler, which allows an authenticated user to cause memory exhaustion or unbounded disk consumption via a crafted .boardarchive file uploaded to the import endpoint.. Mattermost Advisory ID: MMSA-2026-00713

Quoted source text, attributed separately from HOL analysis.