Trending
CVE-2026-4646

CVE detail

CVE-2026-4646

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate user-supplied input in API request handlers which allows an authenticated attacker to crash the plugin process via a crafted HTTP request to the PR details endpoint.. Mattermost Advisory ID: MMSA-2026-00638

CVSS 4.3 · MediumBuzz score 11.9

Buzz score

Why this CVE is surfacing

Buzz score total 11.9

This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.

Buzz score components · mention 6.9 · diversity 5.0 · KEV 0.0 · OTX 0.0 · PoC 0.0

Mention score

6.9

1 evidence mentions in the snapshot

Diversity score

5.0

1 sources across 1 categories

KEV score

0.0

No KEV entry observed

OTX score

0.0

0 OTX pulses

PoC score

0.0

0 repos · best confidence N/A

Best PoC traction

Maximum stars on a matched PoC repo

Why it matters now

Mention timeline

Total mentions: 0; within the 30d window
Peak daily: 0; highest bucket

Evidence

Source links by recency

Newest mentions first

1 source links · newest first

https://mattermost.com/security-updatesmattermost.com
No excerpt available.
Vendor Advisorymattermost.comMay 22, 2026, 11:16 AM

Exploit code

Public exploit repository references

Public PoC repositories are third-party, potentially unsafe artifacts. Treat their code as untrusted and use it only on authorized systems in an isolated, least-privilege environment. cvebuzz does not execute the code or verify that an exploit works.

0 repository references · best confidence N/A · max 0 stars

No public PoC repositories have been matched yet.

Related records

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External lookup

Potential internet exposure

Potential exposure only — not proof of vulnerability.Shodan results indicate potentially internet-exposed products, not confirmed vulnerable systems. They do not confirm that any returned system is vulnerable to CVE-2026-4646.

Product-level CPE searches intentionally omit version fields and NVD version-range or configuration certainty. Verify the exact product version and configuration independently.

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Product CPE queries

Derived from this CVE's existing NVD CPE 2.3 records; the application, operating-system, or hardware part is retained.

cpe:2.3:a:mattermost:mattermost_serverSearch this product on Shodan

Exact CVE query

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Metadata

Canonical fields

NVD status

Analyzed

Published

May 22, 2026

Modified

Jul 23, 2026

Official record

Authoritative NVD record

CVSS vector

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

CWE IDs

Vendor classifications

How this vector reads

CVSS 3.1 base metrics decoded below. This explanation does not recalculate or change the NVD score.

Attack Vector (AV): Network. The vulnerable system can be reached across network boundaries.
Attack Complexity (AC): Low. No special conditions beyond the attacker-controlled steps are required.
Privileges Required (PR): Low. The attacker needs basic user-level privileges.
User Interaction (UI): None. Exploitation does not require another user to act.
Scope (S): Unchanged. Impacts remain within the vulnerable security authority.
Confidentiality Impact (C): None. There is no direct impact to this security property.
Integrity Impact (I): None. There is no direct impact to this security property.
Availability Impact (A): Low. There is a limited impact to this security property.

Signals

Exploitation indicators

0 stored signals · no KEV · 0 OTX pulses