Answer in brief
CVE-2026-13426 records a Medium severity (CVSS 5.4) vulnerability in Client4 fails to validate path parameters. The current sources do not mark it as known exploited. The current feed maps Mattermost/github.com/mattermost/mattermost/server/public (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 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.
The current feed maps Mattermost/github.com/mattermost/mattermost/server/public (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Mattermost/github.com/mattermost/mattermost/server/publicgeneric | >=v0.0.0 <v0.1.22 | v0.1.22 |
Published upstream
Jun 26, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 26, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 26, 2026
The Mattermost Go module github.com/mattermost/mattermost/server/public versions < v0.1.22 fail to validate path parameters when constructing API route paths which allows an attacker to redirect API calls to unintended endpoints via crafted IDs containing path traversal components. Mattermost Advisory ID: MMSA-2025-00532
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-13426 records a Medium severity (CVSS 5.4) vulnerability in Client4 fails to validate path parameters. The current sources do not mark it as known exploited. The current feed maps Mattermost/github.com/mattermost/mattermost/server/public (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 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.
The current feed maps Mattermost/github.com/mattermost/mattermost/server/public (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Mattermost/github.com/mattermost/mattermost/server/publicgeneric | >=v0.0.0 <v0.1.22 | v0.1.22 |
Published upstream
Jun 26, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 26, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 26, 2026
The Mattermost Go module github.com/mattermost/mattermost/server/public versions < v0.1.22 fail to validate path parameters when constructing API route paths which allows an attacker to redirect API calls to unintended endpoints via crafted IDs containing path traversal components. Mattermost Advisory ID: MMSA-2025-00532
Quoted source text, attributed separately from HOL analysis.