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NVD / CVE Program· CNA Mattermost

CVE-2026-2462: Admin RCE via Malicious Plugin Upload on CI Test Instances

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: 0.34% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. Administrator privileges are required. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

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 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to restrict plugin installation on CI test instances with default admin credentials which allows an unauthenticated attacker to achieve remote code execution and exfiltrate sensitive configuration data including AWS and SMTP credentials via uploading a malicious plugin after changing the import directory. Mattermost Advisory ID: MMSA-2025-00528

MediumCVSS 6.6 · v3.1—No exploit No fix recorded
Published
Mar 16, 2026
Updated
Jun 17, 2026
EPSS
0.3% · 28th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.6 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Mattermost
6.6
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
  • No fixed version yet

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

Follow CVE-2026-2462

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 server10.11.0 and later · before 10.11.11
  • mattermost mattermost server11.2.0 and later · before 11.2.3
  • mattermost mattermost server11.3.0 and later · before 11.3.1

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

    • 11.4.0, 11.3.1, 11.2.3, 10.11.11not affected
    • 11.3.0 and later · up to and including 11.3.0affected · semver
    • 11.2.0 and later · up to and including 11.2.2affected · semver
    • 10.11.0 and later · up to and including 10.11.10affected · semver

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-2026-2458Mar 16, 2026 · Unauthorized channel enumeration in private teams after member removal
    17Monitor
  • ← EarlierCVE-2026-2461Mar 16, 2026 · Missing authorization check allows unauthorized modification of other users' comments on a board
    17Monitor
  • Later →CVE-2026-2463Mar 16, 2026 · Unauthorized access to invite ID during team creation
    17Monitor

Remediation

Which version to upgrade to

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

No fix version is recorded for this entry. Check the references for vendor advisories.

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.

No history yet (it accumulates with the daily EPSS job).

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-2026-738788 days apartMattermost group syncable endpoints allow privilege escalation via scheme_admin
    35Monitor
  • CVE-2025-25274360 days apartUnauthorized Command Execution in Archived Channels
    35Monitor
  • CVE-2026-9816154 days apartInsufficient server-side validation of board member role fields permits privilege escalation
    33Monitor
  • CVE-2026-673988 days apartMattermost: Delegated admins could patch protected default system roles
    28Monitor
  • CVE-2026-10106119 days apartUnauthorized users can trigger interactive post actions in private channels via action cookie channel mismatch in Mattermost
    26Monitor
  • CVE-2026-9859154 days apartMattermost Boards plugin didn’t enforce role-based authorization on board channel link allowing board editors to expose boards to arbitrary channels
    26Monitor

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-2026-099928 days apartAuthentication bypass via userID login when email and username login are disabled
    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.
  • Administrator privileges are required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
low · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
Low

Weakness class (CWE)

CWE-863 · Incorrect Authorization

CVSS vector

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

nvd-secondary

Attack context

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

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

All records