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Medium 4.3Published Sep 14, 2026

CVE-2026-13417Boards plugin denial of service via unvalidated block fields.properties

Updated under an hour ago ()

Does this affect you?

It affects Mattermost and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate the type of `fields.properties` on block creation which allows an authenticated user with editor access to a board to crash the Boards plugin worker and trigger a denial of service via a child block whose `fields.properties` is a non-object value. Mattermost Advisory ID: MMSA-2026-00710

CVSS
4.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE)
CWE-754
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Mattermost
NVD analysis
Analyzed
Record last updated
Sep 14, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Mattermost Mattermost
mattermost:mattermost (from the name)
from 11.9.0 through 11.9.0; from 11.8.0 through 11.8.4; from 11.7.0 through 11.7.7; from 10.11.0 through 10.11.22; 11.10.0 not affected; 11.9.1 not affected; 11.8.5 not affected; 11.7.8 not affected; and 1 more ranges
CNA record
mattermost mattermost_server
mattermost:mattermost_server
from 10.11.0 before 10.11.23; from 11.7.0 before 11.7.8; from 11.8.0 before 11.8.5; from 11.9.0 before 11.9.1
NVD

References

  • vendor-advisory

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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