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CVE-2025-6465· NVD / CVE Program· CNA Mattermost

Path traversal in image upload with preview overwrite

Noroxi assessment

Priority: Monitor (action score 17/100)

  • 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: 0.76% (FIRST EPSS); higher than 54.7% of all records.
  • 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) 10.10.1, 10.10.1+incompatible, 10.5.9; github.com/mattermost/mattermost/server/v8 (Go) 8.0.0-20250708173752-d6b35c41f0ae5.

Low priority for now. Upgrade to github.com/mattermost/mattermost-server (Go) 10.10.1, 10.10.1+incompatible, 10.5.9; github.com/mattermost/mattermost/server/v8 (Go) 8.0.0-20250708173752-d6b35c41f0ae5 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 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to sanitize file names which allows users with file upload permission to overwrite file attachment thumbnails via path traversal in file streaming APIs.

MediumCVSS 4.3 · v3.1—No exploit Fix available
Published
Aug 21, 2025
Updated
Jun 17, 2026
EPSS
0.7% · 54th percentile

Report tools

JSON

Action score

17

Monitor

Low priority for now.

CVSS
17 / 40 · 4.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Mattermost
4.3
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-2025-6465

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

Affected versions

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

  • mattermost mattermost server10.5.0 and later · before 10.5.9
  • mattermost mattermost server10.8.0 and later · before 10.8.4
  • mattermost mattermost server10.9.0 and later · before 10.9.4
  • mattermost mattermost server10.10.0

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

    • 10.11.0, 10.8.4, 10.5.9, 10.10.1, 10.9.4not affected
    • 10.10.0affected
    • 10.8.0 and later · up to and including 10.8.3affected · semver
    • 10.5.0 and later · up to and including 10.5.8affected · semver
    • 10.9.0 and later · up to and including 10.9.3affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Gogithub.com/mattermost/mattermost-serverfrom 10.10.0 · before 10.10.110.10.1
Gogithub.com/mattermost/mattermost-serverfrom 10.10.0+incompatible · before 10.10.1+incompatible10.10.1+incompatible
Gogithub.com/mattermost/mattermost-serverfrom 10.5.0 · before 10.5.910.5.9
Gogithub.com/mattermost/mattermost-serverfrom 10.5.0+incompatible · before 10.5.9+incompatible10.5.9+incompatible
Gogithub.com/mattermost/mattermost-serverfrom 10.8.0 · before 10.8.410.8.4
Gogithub.com/mattermost/mattermost-serverfrom 10.8.0+incompatible · before 10.8.4+incompatible10.8.4+incompatible
Gogithub.com/mattermost/mattermost-serverfrom 10.9.0 · before 10.9.410.9.4
Gogithub.com/mattermost/mattermost-serverfrom 10.9.0+incompatible · before 10.9.4+incompatible10.9.4+incompatible
Gogithub.com/mattermost/mattermost-server/v5from 0—
Gogithub.com/mattermost/mattermost-server/v6from 0—
Gogithub.com/mattermost/mattermost/server/v8from 0—
Gogithub.com/mattermost/mattermost/server/v8before 8.0.0-20250708173752-d6b35c41f0ae58.0.0-20250708173752-d6b35c41f0ae5

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-2025-53971Aug 21, 2025 · Channel and Team Membership APIs inadvertently allow loss of Member privileges.
    15Monitor
  • ← EarlierCVE-2025-8023Aug 21, 2025 · Path Traversal in Template Upload Allows Uploading Files Outside Target Directory
    19Monitor
  • Later →CVE-2025-8402Aug 21, 2025 · Nil pointer dereference in bulk import crashes server
    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-server10.10.1Package registry (OSV)
Go:github.com/mattermost/mattermost-server10.10.1+incompatiblePackage registry (OSV)
Go:github.com/mattermost/mattermost-server10.5.9Package registry (OSV)
Go:github.com/mattermost/mattermost-server10.5.9+incompatiblePackage registry (OSV)
Go:github.com/mattermost/mattermost-server10.8.4Package registry (OSV)
Go:github.com/mattermost/mattermost-server10.8.4+incompatiblePackage registry (OSV)
Go:github.com/mattermost/mattermost-server10.9.4Package registry (OSV)
Go:github.com/mattermost/mattermost-server10.9.4+incompatiblePackage registry (OSV)
Go:github.com/mattermost/mattermost/server/v88.0.0-20250708173752-d6b35c41f0ae5Package 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

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-2026-4858273 days apartPath traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.
    39Monitor
  • CVE-2025-25279178 days apartArbitrary file read in Mattermost Boards via import & export board archive
    37Monitor
  • CVE-2026-6961295 days apartCVE-2026-6961: Path traversal via unsanitized FileInfo.Name in Mattermost federation sync
    30Monitor
  • CVE-2025-907929 days apartAdmin RCE via prepackaged plugins by way of misconfigured imports directory
    28Monitor
  • CVE-2025-20051178 days apartArbitrary file read via block duplication in Mattermost Boards
    26Monitor
  • CVE-2026-7521341 days apartSAML certificate deletion allows path traversal to delete arbitrary files outside the config directory
    22Monitor

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-2025-5507085 days apartLack of MFA enforcement in WebSocket connections
    30Monitor
  • CVE-2025-478700 days apartTeam invite ID leaked to team admin with no member invite privileges
    17Monitor
  • CVE-2025-13870103 days apartUnauthorized access and subscription vulnerability in Boards
    17Monitor

Bug bounty scope

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

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
none
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

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

nvd-secondary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

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

Vulnerable

ts
const file = path.join(ROOT, req.query.name);res.sendFile(file);

Fixed

ts
const file = path.resolve(ROOT, req.query.name);if (!file.startsWith(ROOT + path.sep)) {  return res.sendStatus(400);}res.sendFile(file);

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

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

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

All records