Answer in brief
CVE-2026-75588 records a Low severity (CVSS 2.6) vulnerability in Mattermost Desktop App plugin popout scheme validation bypass. The current sources do not mark it as known exploited. The current feed maps Mattermost/Mattermost (generic), 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.
CVSS is 2.6. 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.
The current feed maps Mattermost/Mattermost (generic), Mattermost/Mattermost (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:mattermost:mattermost_desktop:*:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Mattermost/Mattermostgeneric | 0 | Not reported |
| Mattermost/Mattermostgeneric | >=0 <=6.2.2 | Not reported |
Published upstream
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 17, 2026
Mattermost Desktop App versions <=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717
Quoted source text, attributed separately from HOL analysis.