CVE-2021-0256 - CVE House
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Status published Medium CVE-2021-0256

Junos OS: mosquitto Local Privilege Escalation vulnerability in SUID binaries

Vulnerability Description

A sensitive information disclosure vulnerability in the mosquitto message broker of Juniper Networks Junos OS may allow a locally authenticated user with shell access the ability to read portions of sensitive files, such as the master.passwd file. Since mosquitto is shipped with setuid permissions enabled and is owned by the root user, this vulnerability may allow a local privileged user the ability to run mosquitto with root privileges and access sensitive information stored on the local filesystem. This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S12, 17.4 versions prior to 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.3 versions prior to 18.3R3-S4; 19.1 versions prior to 19.1R3-S4; 19.3 versions prior to 19.3R3-S1, 19.3R3-S2; 19.4 versions prior to 19.4R2-S3; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R1-S3, 20.2R2, 20.2R3.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • Juniper SIRT would like to acknowledge and thank Hoàng Thạch Nguyễn (d4rkn3ss) of STAR Labs for responsibly reporting this vulnerability.

Affected Vendor

Juniper Networks

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Affected Software

Junos OS
Vulnerable Versions:
17.3, 17.4, 18.1, 18.3, 19.1, 19.3, 19.4, 20.1, 20.2

Timeline

Official Publish: April 22nd, 2021
Last Modified: September 16th, 2024
Added to House: July 21st, 2026

CVSS Vectors

V3: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Weaknesses (CWE)