DoS via Channel Notification Properties

published 2023-09-29 3 y ago modified 2026-06-17 4 mo ago also GHSA-33r7-wjfc-7w98 , EUVD-2023-2399

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.7%; EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits: 0; none known

Mattermost fails to enforce character limits in all possible notification props allowing an attacker to send a really long value for a notification_prop resulting in the server consuming an abnormal quantity of computing resources and possibly becoming temporarily unavailable for its users.

Patch / fix

fixed in 3

go github.com/mattermost/mattermost/server/v8 8.0.2, 8.1.1
go github.com/mattermost/mattermost-server/v6 7.8.10
Mattermost Mattermost 7.8.10, 8.0.2, 8.1.1

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 y ago (2024-09-20)

Exploit prediction

0.68% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

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

Affected packages

ecosystem	package	affected	fixed in
go	github.com/mattermost/mattermost/server/v8	>=8.1.0, <8.1.1 >=8.0.0, <8.0.2	8.1.1 8.0.2
go	github.com/mattermost/mattermost-server/v6	<7.8.10	7.8.10

Affected products

Mattermost Mattermost

Classification

Weakness

CWE-400 Uncontrolled Resource Consumption

References

mattermost.com /security-updates
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2023-5196
advisory
github.com /mattermost/mattermost
package

Sources

CVE List CVE-2023-5196
GitHub Advisory GHSA-33r7-wjfc-7w98
NVD CVE-2023-5196

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.

Summary