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Fencer Vulns
medium 4.3

CVE-2025-20033 json

DoS via custom post type for sysconsole plugin readers

published 2025-01-09 21 mo ago modified 2026-09-10 1 mo ago also GHSA-2549-xh72-qrpm , GO-2025-3379 , EUVD-2025-0004

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

Mattermost versions 10.2.0, 9.11.x <= 9.11.5, 10.0.x <= 10.0.3, 10.1.x <= 10.1.3 fail to properly validate post types, which allows attackers to deny service to users with the sysconsole_read_plugins permission via creating a post with the custom_pl_notification type and specific props.

Patch / fix

  • go github.com/mattermost/mattermost/server/v8 8.0.0-20250102081831-64c566a8280b, 9.11.16, 10.0.4, 10.1.4, 10.2.1
  • go github.com/mattermost/mattermost-server 10.0.4+incompatible, 10.1.4+incompatible, 10.2.1+incompatible
  • Mattermost Mattermost 9.11.6, 10.0.4, 10.1.4, 10.2.1, 10.3.0
  • govulncheck-vulndb SLE Module for Package Hub 15 SP6, openSUSE Leap 15.6 0.0.20250128T150132-150000.1.29.1

suse advisories SUSE-SU-2025:0297-1

  • govulncheck-vulndb openSUSE Tumbleweed 0.0.20250109T194159-1.1

opensuse advisories openSUSE-SU-2025:14644-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-20033 updated cvss 4.3

mattermost: DoS via custom post type for sysconsole plugin readers

  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/acm-grafana-rhel8 Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8, advanced-cluster-security/rhacs-roxctl-rhel8, advanced-cluster-security/rhacs-rhel8-operator, advanced-cluster-security/rhacs-central-db-rhel8, advanced-cluster-security/rhacs-scanner-v4-rhel8, advanced-cluster-security/rhacs-scanner-v4-db-rhel8 Red Hat Ceph Storage 5 rhceph/rhceph-5-dashboard-rhel8 Red Hat Ceph Storage 6 rhceph/rhceph-6-dashboard-rhel9 Red Hat Ceph Storage 8 rhceph/grafana-rhel9 Red Hat OpenShift GitOps openshift-gitops-1/dex-rhel8
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
21 mo ago

Exploit prediction

0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
go github.com/mattermost/mattermost/server/v8
>=9.11.0, <9.11.16
>=10.0.0, <10.0.4
>=10.1.0, <10.1.4
>=10.2.0, <10.2.1
<8.0.0-20250102081831-64c566a8280b
9.11.16
10.0.4
10.1.4
10.2.1
8.0.0-20250102081831-64c566a8280b
go github.com/mattermost/mattermost-server
>=10.0.0+incompatible, <10.0.4+incompatible
>=10.1.0+incompatible, <10.1.4+incompatible
>=10.2.0+incompatible, <10.2.1+incompatible
10.0.4+incompatible
10.1.4+incompatible
10.2.1+incompatible
go github.com/mattermost/mattermost-server/v5
all versions
 no fix listed
go github.com/mattermost/mattermost-server/v6
all versions
 no fix listed

Affected products

  • Mattermost Mattermost

Classification

Weakness
  • CWE-1287 Improper Validation of Specified Type of Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.