Skip to content
Noroxi
NVD / CVE Program· CNA Mattermost

CVE-2025-8285: Unauthorized Channel Subscription Creation in Mattermost Confluence Plugin

Noroxi assessment

Priority: Monitor (action score 21/100)

  • 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: 0.19% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Mattermost Mattermost Confluence Plugin 1.5.0.

Low priority for now. Upgrade to Mattermost Mattermost Confluence Plugin 1.5.0 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 Confluence Plugin version <1.5.0 fails to check the access of the user to the channel which allows attackers to create channel subscription without proper access to the channel via API call to the create channel subscription endpoint.

MediumCVSS 5.3 · v3.1—No exploit Fix available
Published
Aug 11, 2025
Updated
Jun 17, 2026
EPSS
0.1% · 8th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.3
CNA · Mattermost
4.0
1.3 point gap

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

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-2025-8285

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

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for mattermost records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

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.

We use this product, ask for help

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
mattermostconfluence

Affected versions

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

  • mattermost confluencebefore 1.5.0

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 Confluence Plugin

    • 1.5.0not affected
    • before 1.5.0affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Gogithub.com/mattermost/mattermost-plugin-confluencebefore 1.5.01.5.0
openSUSE:Tumbleweedgovulncheck-vulndbbefore 0.0.20250818T190335-1.10.0.20250818T190335-1.1

Same product

mattermost: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-54525Unexpected input to Create Channel Subscription endpoint causes DoS in Mattermost Confluence Plugin
    30Monitor
  • CVE-2025-54463Unexpected Input to Cloud Webhook endpoint Causes DoS in Mattermost Confluence Plugin
    30Monitor
  • CVE-2025-52931Unexpected input to Update Channel Subscription endpoint causes DoS in Mattermost Confluence Plugin
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-54458Aug 11, 2025 · Unauthorized Subscription Creation to Confluence Space in Mattermost Confluence Plugin
    20Monitor
  • ← EarlierCVE-2025-54478Aug 11, 2025 · Unauthenticated Channel Subscription Edit in Mattermost Confluence Plugin
    21Monitor
  • Later →CVE-2025-13523Feb 6, 2026 · Cross-Site Scripting (XSS) via Unescaped Display Names in Mattermost Confluence Plugin OAuth2 Flow
    21Monitor

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
Mattermost Mattermost Confluence Plugin1.5.0Vendor (CNA)
Go:github.com/mattermost/mattermost-plugin-confluence1.5.0Package registry (OSV)
opensuse:govulncheck-vulndb0.0.20250818T190335-1.1 · openSUSE:TumbleweedPackage 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-2025-487310 days apartUnauthorized Subscription Edit to Confluence Space in Mattermost Confluence Plugin
    25Monitor
  • CVE-2025-544580 days apartUnauthorized Subscription Creation to Confluence Space in Mattermost Confluence Plugin
    20Monitor
  • CVE-2025-440010 days apartUnauthorized Channel Subscription Read in Mattermost Confluence Plugin
    16Monitor
  • CVE-2025-539100 days apartUnauthorized Channel Subscription Edit in Mattermost Confluence Plugin
    16Monitor
  • CVE-2025-492210 days apartUnauthenticated Access to Channel Subscription in Mattermost Confluence Plugin
    14Monitor
  • CVE-2025-538570 days apartLack of Authorization on Get Channel Subscriptions for Autocomplete in Mattermost Confluence Plugin
    14Monitor

Chain candidates

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

—

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.
  • No account or password is required.
  • 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
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-862 · Missing Authorization

CVSS vector

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

nvd-primary

Attack context

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

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