Denial of Service via crashing the Calls Plugin

published 2023-11-06 3 y ago modified 2026-06-17 4 mo ago also GHSA-xvq6-h898-wcj8 , EUVD-2023-3066

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

Mattermost fails to properly validate requests to the Calls plugin, allowing an attacker sending a request without a User Agent header to cause a panic and crash the Calls plugin

Patch / fix

fixed in 3

go github.com/mattermost/mattermost-server/v6 7.8.12
go github.com/mattermost/mattermost/server/v8 8.0.4, 8.1.3, 9.0.1
Mattermost Mattermost 7.8.12, 8.0.4, 8.1.3

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 y ago (2024-09-04)

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	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
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/v6	<7.8.12	7.8.12
go	github.com/mattermost/mattermost/server/v8	>=8.0.0, <8.0.4 >=8.1.0, <8.1.3 >=9.0.0, <9.0.1	8.0.4 8.1.3 9.0.1

Affected products

Mattermost Mattermost

Classification

Weakness

CWE-754 Improper Check for Unusual or Exceptional Conditions

References

mattermost.com /security-updates
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2023-5967
advisory
github.com /mattermost/mattermost
package

Sources

CVE List CVE-2023-5967
GitHub Advisory GHSA-xvq6-h898-wcj8
NVD CVE-2023-5967

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