CVE-2021-0256

Junos OS: mosquitto Local Privilege Escalation vulnerability in SUID binaries

MEDIUM

5.5

CVSS Score

Published: April 22, 2021 at 07:37 PM UTC

Updated: June 17, 2026 at 03:29 AM UTC

1 product affected across 1 vendorJunos

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Severity

MEDIUM5.5

Exploit prediction

EPSS 0.2%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Junos · Juniper Networks

95%

17.3 ≤ v < 17.3R3-S1217.4 ≤ v < 17.4R3-S418.1 ≤ v < 18.1R3-S1218.3 ≤ v < 18.3R3-S419.1 ≤ v < 19.1R3-S419.3 ≤ v < 19.3R3-S1, 19.3R3-S219.4 ≤ v < 19.4R2-S320.1 ≤ v < 20.1R220.2 ≤ v < 20.2R1-S3, 20.2R2, 20.2R317.3 17.3 r1 17.3 r1-s1 17.3 r1-s4 17.3 r2 17.3 r2-s1 17.3 r2-s2 17.3 r2-s3 17.3 r2-s4 17.3 r2-s5 17.3 r3 17.3 r3-s1 17.3 r3-s10 17.3 r3-s11 17.3 r3-s2 17.3 r3-s3 17.3 r3-s4 17.3 r3-s5 17.3 r3-s6 17.3 r3-s7 17.3 r3-s8 17.3 r3-s9 17.4 17.4 r1 17.4 r1-s1 17.4 r1-s2 17.4 r1-s3 17.4 r1-s4 17.4 r1-s5 17.4 r1-s6 17.4 r1-s7 17.4 r2 17.4 r2-s1 17.4 r2-s10 17.4 r2-s11 17.4 r2-s12 17.4 r2-s2 17.4 r2-s3 17.4 r2-s4 17.4 r2-s5 17.4 r2-s6 17.4 r2-s7 17.4 r2-s8 17.4 r2-s9 17.4 r3 17.4 r3-s1 17.4 r3-s2 17.4 r3-s3 18.1 18.1 r1 18.1 r2 18.1 r2-s1 18.1 r2-s2 18.1 r2-s4 18.1 r3 18.1 r3-s1 18.1 r3-s10 18.1 r3-s11 18.1 r3-s2 18.1 r3-s3 18.1 r3-s4 18.1 r3-s5 18.1 r3-s6 18.1 r3-s7 18.1 r3-s8 18.1 r3-s9 18.2 18.2 r1 18.2 r1-s2 18.2 r1-s3 18.2 r1-s4 18.2 r1-s5 18.2 r2 18.2 r2-s1 18.2 r2-s2 18.2 r2-s3 18.2 r2-s4 18.2 r2-s5 18.2 r2-s6 18.2 r2-s7 18.2 r3 18.2 r3-s1 18.2 r3-s2 18.2 r3-s3 18.2 r3-s4 18.2 r3-s5 18.2 r3-s6 18.3 18.3 r1 18.3 r1-s1 18.3 r1-s2 18.3 r1-s3 18.3 r1-s4 18.3 r1-s5 18.3 r1-s6 18.3 r2 18.3 r2-s1 18.3 r2-s2 18.3 r2-s3 18.3 r2-s4 18.3 r3 18.3 r3-s1 18.3 r3-s2 18.3 r3-s3 18.4 18.4 r1 18.4 r1-s1 18.4 r1-s2 18.4 r1-s3 18.4 r1-s4 18.4 r1-s5 18.4 r1-s6 18.4 r1-s7 18.4 r2 18.4 r2-s1 18.4 r2-s2 18.4 r2-s3 18.4 r2-s4 18.4 r2-s5 18.4 r2-s6 18.4 r3 18.4 r3-s1 18.4 r3-s2 18.4 r3-s3 18.4 r3-s4 18.4 r3-s5 18.4 r3-s6 19.1 19.1 r1 19.1 r1-s1 19.1 r1-s2 19.1 r1-s3 19.1 r1-s4 19.1 r1-s5 19.1 r2 19.1 r2-s1 19.1 r3 19.1 r3-s1 19.1 r3-s2 19.1 r3-s3 19.2 19.2 r1 19.2 r1-s1 19.2 r1-s2 19.2 r1-s3 19.2 r1-s4 19.2 r1-s5 19.2 r2 19.2 r2-s1 19.2 r3 19.2 r3-s1 19.3 19.3 r1 19.3 r1-s1 19.3 r2 19.3 r2-s1 19.3 r2-s2 19.3 r2-s3 19.3 r2-s4 19.3 r2-s5 19.3 r3 19.4 19.4 r1 19.4 r1-s1 19.4 r1-s2 19.4 r2 19.4 r2-s1 19.4 r2-s2 19.4 r3 19.4 r3-s1 20.1 20.1 r1 20.1 r1-s1 20.1 r1-s2 20.1 r1-s3 20.1 r1-s4 20.2 20.2 r1 20.2 r1-s1 20.2 r1-s2 20.2 r1-s3 20.2 r2 20.3 r1 20.4 r1 20.4 r1-s1

Affected range stops below 17.3R3-S12, so it looks safe — our inference, not a vendor statement

Affected range stops below 17.4R3-S4, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.1R3-S12, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.3R3-S4, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.1R3-S4, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.3R3-S1, 19.3R3-S2, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.4R2-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.1R2, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.2R1-S3, 20.2R2, 20.2R3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://kb.juniper.net/JSA11175

References (1)

x_refsource_MISCVendor Advisory

Source: [email protected]

https://kb.juniper.net/JSA11175

CVSS

5.5MEDIUMjuniper

Attack Vector: LOCAL
Complexity: LOW
Privileges: LOW
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: HIGH
Integrity: NONE
Availability: NONE

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-250CWE-269

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