CVE-2025-20051 | Arbitrary file read via block duplication in Mattermost Boards

Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to properly validate input when patching and duplicating a board, which allows a user to read any arbitrary file on the system via duplicating a specially crafted block in Boards.

Published: 2025-02-24 Last update: 2025-08-18 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-20051 is rated Moderate Risk (54.7/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.57%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-20051

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.33% 0.57% +0.24%
2 2026-04-13 0.24% 0.33% +0.09%
3 2026-04-04 — 0.24% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-20051

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.9 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.1 6.0 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 3.6 [email protected]

Weakness enumeration for CVE-2025-20051

GitHub Security Advisory for CVE-2025-20051

GHSA-v469-7wp6-7cvp · Severity: critical · Ecosystem: go — Mattermost allows reading arbitrary files

Affected software / configurations for CVE-2025-20051

Vendor Product Version Raw CPE
mattermost mattermost_server >= 9.11.0, < 9.11.8 cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
mattermost mattermost_server >= 10.2.0, < 10.2.3 cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
mattermost mattermost_server >= 10.3.0, < 10.3.3 cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
mattermost mattermost_server >= 10.4.0, < 10.4.2 cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

References for CVE-2025-20051

URL Tags
https://mattermost.com/security-updates Vendor Advisory
cvelogic Threat Intelligence