A vulnerability has been identified in Rocket.Chat, where the ACL checks in the Slash Command /mute occur after checking whether a user is…

published 2023-05-11 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-32055

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits: 0; none known

A vulnerability has been identified in Rocket.Chat, where the ACL checks in the Slash Command /mute occur after checking whether a user is a member of a given channel, leaking private channel members to unauthorized users. This allows authenticated users to enumerate whether a username is a member of a channel that they do not have access to.

Patch / fix

fixed in 1

rocket.chat rocket.chat 6.0.0

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 21 mo ago (2025-01-27)

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

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

Affected products

n/a Rocket.Chat

Classification

Weakness

CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
CWE-863 Incorrect Authorization

References

hackerone.com /reports/1445810
issue-tracking, third-party-advisory

Sources

CVE List CVE-2023-28357
NVD CVE-2023-28357

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