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NVD / CVE Program· CNA Mattermost

CVE-2025-6226: IDOR in CreatePost API allows for timeboxed message disclosure

MediumCVSS 6.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 26/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.37% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: github.com/mattermost/mattermost-server (Go) 10.5.7, 10.5.7+incompatible, 10.7.4; github.com/mattermost/mattermost/server/v8 (Go) 8.0.0-20250520130510-fa40a8c5d47f.

Low priority for now. Upgrade to github.com/mattermost/mattermost-server (Go) 10.5.7, 10.5.7+incompatible, 10.7.4; github.com/mattermost/mattermost/server/v8 (Go) 8.0.0-20250520130510-fa40a8c5d47f or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Mattermost versions 10.5.x <= 10.5.6, 10.8.x <= 10.8.1, 10.7.x <= 10.7.3, 9.11.x <= 9.11.16 fail to verify authorization when retrieving cached posts by PendingPostID which allows an authenticated user to read posts in private channels they don't have access to via guessing the PendingPostID of recently created posts.

Published
Jul 18, 2025
Updated
Jun 17, 2026
EPSS
0.3% · 31th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Mattermost
6.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-6226

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
mattermostmattermost server

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Mattermost). Independent of NVD's CPE analysis and usually ahead of it.

  • Mattermost Mattermost

    • 10.9.0, 10.5.8, 10.8.2, 10.7.4, 9.11.17not affected
    • 10.5.0 and later · up to and including 10.5.6affected · semver
    • 10.8.0 and later · up to and including 10.8.1affected · semver
    • 10.7.0 and later · up to and including 10.7.3affected · semver
    • 9.11.0 and later · up to and including 9.11.16affected · semver
Affected versions · NVD (4)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • mattermost mattermost server9.11.0 and later · before 9.11.17
  • mattermost mattermost server10.5.0 and later · before 10.5.7
  • mattermost mattermost server10.7.0 and later · before 10.7.4
  • mattermost mattermost server10.8.0 and later · before 10.8.2

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Gogithub.com/mattermost/mattermost-serverfrom 10.5.0 · before 10.5.710.5.7
Gogithub.com/mattermost/mattermost-serverfrom 10.5.0+incompatible · before 10.5.7+incompatible10.5.7+incompatible
Gogithub.com/mattermost/mattermost-serverfrom 10.7.0 · before 10.7.410.7.4
Gogithub.com/mattermost/mattermost-serverfrom 10.7.0+incompatible · before 10.7.4+incompatible10.7.4+incompatible
Gogithub.com/mattermost/mattermost-serverfrom 10.8.0 · before 10.8.210.8.2
Gogithub.com/mattermost/mattermost-serverfrom 10.8.0+incompatible · before 10.8.2+incompatible10.8.2+incompatible
Gogithub.com/mattermost/mattermost-serverfrom 9.11.0 · before 9.11.179.11.17
Gogithub.com/mattermost/mattermost-serverfrom 9.11.0+incompatible · before 9.11.17+incompatible9.11.17+incompatible
Gogithub.com/mattermost/mattermost-server/v5from 0—
Gogithub.com/mattermost/mattermost-server/v6from 0—
Gogithub.com/mattermost/mattermost/server/v8before 8.0.0-20250520130510-fa40a8c5d47f8.0.0-20250520130510-fa40a8c5d47f

Same product

mattermost: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-4858Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.
    39Monitor
  • CVE-2025-12421Account Takeover via Code Exchange Endpoint
    39Monitor
  • CVE-2025-12419Account takeover on OAuth/OpenID-enabled servers
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-46702Jun 30, 2025 · Mattermost Playbooks allows privilege escalation through improper access control in playbook run participant management
    21Monitor
  • ← EarlierCVE-2025-47871Jun 30, 2025 · Mattermost Playbooks exposes private channel metadata to unauthorized users via run metadata API
    21Monitor
  • Later →CVE-2025-6233Jul 18, 2025 · Arbitrary file read by system admin via path traversal
    19Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Go:github.com/mattermost/mattermost-server10.5.7Package registry (OSV)
Go:github.com/mattermost/mattermost-server10.5.7+incompatiblePackage registry (OSV)
Go:github.com/mattermost/mattermost-server10.7.4Package registry (OSV)
Go:github.com/mattermost/mattermost-server10.7.4+incompatiblePackage registry (OSV)
Go:github.com/mattermost/mattermost-server10.8.2Package registry (OSV)
Go:github.com/mattermost/mattermost-server10.8.2+incompatiblePackage registry (OSV)
Go:github.com/mattermost/mattermost-server9.11.17Package registry (OSV)
Go:github.com/mattermost/mattermost-server9.11.17+incompatiblePackage registry (OSV)
Go:github.com/mattermost/mattermost/server/v88.0.0-20250520130510-fa40a8c5d47fPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2025-25068119 days apartBypassing MFA Enforcement on Plugin Endpoints
    35Monitor
  • CVE-2025-55070119 days apartLack of MFA enforcement in WebSocket connections
    30Monitor
  • CVE-2026-6673339 days apartMattermost Jira plugin had unauthenticated {{/ac/installed}} lifecycle callback during pending Jira Cloud install
    25Monitor
  • CVE-2025-55073119 days apartMS Teams plugin OAuth allows editing arbitrary posts
    21Monitor
  • CVE-2025-4787034 days apartTeam invite ID leaked to team admin with no member invite privileges
    17Monitor
  • CVE-2025-13870137 days apartUnauthorized access and subscription vulnerability in Boards
    17Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

  • CVE-2025-498128 days apartPath Traversal Leading to RCE by Any Authenticated Mattermost User
    39Monitor
  • CVE-2025-4922234 days apartMattermost Shared Channel Upload Type Validation Bypass
    27Monitor
  • CVE-2025-62330 days apartArbitrary file read by system admin via path traversal
    19Monitor
  • CVE-2025-646534 days apartPath traversal in image upload with preview overwrite
    17Monitor

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Not on record for this CVE: EPSS history · patch commit or PR link.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-306 · Missing Authentication for Critical Function

CVSS vector

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

nvd-secondary

Root cause

A function added for development or support ships to production without authentication. It often relies on the assumption that it is “only reachable from the internal network.”

The bug in code

The whole CWE-306 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
// Added for the support teamapp.post("/maintenance/reset", resetDevice);

Fixed

ts
if (config.maintenanceEnabled) {  app.post(    "/maintenance/reset",    requireSession, requireRole("admin"), resetDevice  );}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records