CVE-2023-5968

MEDIUM

Mattermost - Exposure of Sensitive Information via User Object Sanitization Failure

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2023-5968. PoCs published by Curtail-Inc.

AI-analyzed exploit summary This repository contains a functional proof-of-concept for CVE-2023-5968, an information leak vulnerability in a Flask-based team-chat API. The flaw is a missing sanitization in the PATCH /users/<id> endpoint, which returns the full user object including the bcrypt password hash, unlike the GET endpoints that properly sanitize the response.

Description

Mattermost fails to properly sanitize the user object when updating the username, resulting in the password hash being included in the response body. 

Exploits (1)

nomisec WORKING POC
by Curtail-Inc · poc
https://github.com/Curtail-Inc/hello-ReGrade-security

This repository contains a functional proof-of-concept for CVE-2023-5968, an information leak vulnerability in a Flask-based team-chat API. The flaw is a missing sanitization in the PATCH /users/<id> endpoint, which returns the full user object including the bcrypt password hash, unlike the GET endpoints that properly sanitize the response.

Classification
Working Poc 98%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Custom Flask-based team-chat API (demonstrated in the repository)
Auth required
Prerequisites: Authenticated access to the API · Ability to send PATCH requests to the /users/<id> endpoint
mistral-large-3 · analyzed Jul 04, 2026 Full analysis →

References (1)

Core 1
Core References

Scores

CVSS v3 4.9
EPSS 0.0051
EPSS Percentile 40.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-116 CWE-200
Status published
Products (5)
mattermost/mattermost 9.0.0
mattermost/mattermost < 7.8.11
mattermost/mattermost 8.0.0 - 8.0.4Go
mattermost/mattermost-server 0 - 5.3.2-0.20230825233148-f787fd63368a (2 CPE variants)Go
mattermost/mattermost-server 5.4.0-rc1 - 7.8.12Go
Published Nov 06, 2023
Tracked Since Feb 18, 2026