How severe is CVE-2025-8023?

CVE-2025-8023 has a CVSS score of 6.8/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2025-8023?

CVE-2025-8023 affects the following packages: github.com/mattermost/mattermost-server (Go), github.com/mattermost/mattermost-server (Go), github.com/mattermost/mattermost-server (Go), github.com/mattermost/mattermost-server (Go), github.com/mattermost/mattermost/server/v8 (Go), github.com/mattermost/mattermost-server/v5 (Go), github.com/mattermost/mattermost-server/v6 (Go). Ecosystems affected: Go.

How do I fix CVE-2025-8023?

Update github.com/mattermost/mattermost-server to 10.8.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-8023 is resolved across your whole dependency graph.

How do I detect CVE-2025-8023 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/mattermost/mattermost-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-8023 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2025-8023 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-8023 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-8023?

CVE-2025-8023 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 35th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-8023?

CVE-2025-8023 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2025-8023 published, and has it been updated?

CVE-2025-8023 was published on August 21, 2025 and was last updated on November 7, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2025-8023 — mattermost-server

MEDIUM

CVE-2025-8023 is a medium-severity (CVSS 6.8) Path Traversal vulnerability in github.com/mattermost/mattermost-server. A fix is available for github.com/mattermost/mattermost-server — see the affected versions and patch details below.

Path Traversal in Template Upload Allows Uploading Files Outside Target Directory

Also known asGHSA-x67c-v8jr-p29rGO-2025-3907

Published

Aug 21, 2025

Updated

Nov 7, 2026

Affected

7 pkgs

Patched

5 / 7

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-8023.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs35th percentile — riskier than 35% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

7 pkgs affected

🐹github.com/mattermost/mattermost-server🐹github.com/mattermost/mattermost-server🐹github.com/mattermost/mattermost-server🐹github.com/mattermost/mattermost-server🐹github.com/mattermost/mattermost/server/v8🐹github.com/mattermost/mattermost-server/v5🐹github.com/mattermost/mattermost-server/v6

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2 fails to sanitize path traversal sequences in template file destination paths, which allows a system admin to perform path traversal attacks via malicious path components, potentially enabling malicious file placement outside intended directories.

Affected Packages

7 total 5 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/mattermost/mattermost-server`	≥ 10.8.0&&< 10.8.4	10.8.4`go get github.com/mattermost/mattermost-server@v10.8.4`
🐹Go	`github.com/mattermost/mattermost-server`	≥ 10.5.0&&< 10.5.9	10.5.9`go get github.com/mattermost/mattermost-server@v10.5.9`
🐹Go	`github.com/mattermost/mattermost-server`	≥ 9.11.0&&< 9.11.18	9.11.18`go get github.com/mattermost/mattermost-server@v9.11.18`
🐹Go	`github.com/mattermost/mattermost-server`	≥ 10.9.0&&< 10.9.3	10.9.3`go get github.com/mattermost/mattermost-server@v10.9.3`
🐹Go	`github.com/mattermost/mattermost/server/v8`	all versions	8.0.0-20250708065844-b38e2eccda18`go get github.com/mattermost/mattermost/server/v8@v8.0.0-20250708065844-b38e2eccda18`
🐹Go	`github.com/mattermost/mattermost-server/v5`	all versions	No fix

Affected Products

1 product · 4 configurations

Application

mattermost servermattermost

≥ 10.9.0 && < 10.9.3

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/mattermost/mattermost-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/mattermost/mattermost-server to 10.8.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-8023 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2025-8023 in your dependencies?

Find it across Go, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.8/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

None

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

CWE Classification

CWE-22Path Traversal

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

Timeline

Disclosed

Aug 21, 2025

Last updated

Nov 7, 2026

Identifiers

CVE-2025-8023

GHSA-x67c-v8jr-p29r

GO-2025-3907

References

Advisorygithub.com · CVE 2025 8023.json Advisorynvd.nist.gov · CVE 2025 8023 Webmattermost.com · security updates Webpkg.go.dev · GO 2025 3907 Packagegithub.com · mattermost

Related vulnerabilities

This CVE is medium severity; 6 of 8 other CVEs affecting mattermost-server are rated as high or higher (top: high).

CVE-2026-5139CVE-2026-8074CVE-2026-9162CVE-2026-6673CVE-2026-6062CVE-2026-8823CVE-2026-6046CVE-2026-7387

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedNov 7, 2026

CVE-2025-8023 — mattermost-server

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2025-8023 in your dependencies?