CVE-2021-31372

Junos OS: J-Web allows a locally authenticated attacker to escalate their privileges to root.

Published Oct 19, 2021 CVSS 3.1 · 8.8 High EPSS 1.2% KEV · Not listed
Description
An Improper Input Validation vulnerability in J-Web of Juniper Networks Junos OS allows a locally authenticated J-Web attacker to escalate their privileges to root over the target device. This issue affects: Juniper Networks Junos OS All versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R3-S9; 19.1 versions prior to 19.1R3-S6; 19.2 versions prior to 19.2R3-S3; 19.3 versions prior to 19.3R3-S3; 19.4 versions prior to 19.4R3-S5; 20.1 versions prior to 20.1R3-S1; 20.2 versions prior to 20.2R3-S2; 20.3 versions prior to 20.3R3-S1; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2, 21.1R3; 21.2 versions prior to 21.2R1-S1, 21.2R2;

Remediation

Vendor Solution

The following software releases have been updated to resolve this specific issue: 18.3R3-S5, 18.4R3-S9, 19.1R3-S6, 19.2R3-S3, 19.3R3-S3, 19.4R3-S5, 20.1R3-S1, 20.2R3-S2, 20.3R3-S1, 20.4R3, 21.1R2, 21.1R3, 21.2R1-S1, 21.2R2, 21.3R1, and all subsequent releases.


Vendor Workaround

To reduce the risk of exploitation of this issue, use access lists or firewall filters to limit access to only trusted administrative networks, hosts and users. Alternatively, J-Web can be disabled.

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2021-18282 An Improper Input Validation vulnerability in J-Web of Juniper Networks Junos OS allows a locally authenticated J-Web attacker to escalate their privileges to root over the target device. This issue affects: Juniper Networks Junos OS All versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R3-S9; 19.1 versions prior to 19.1R3-S6; 19.2 versions prior to 19.2R3-S3; 19.3 versions prior to 19.3R3-S3; 19.4 versions prior to 19.4R3-S5; 20.1 versions prior to 20.1R3-S1; 20.2 versions prior to 20.2R3-S2; 20.3 versions prior to 20.3R3-S1; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2, 21.1R3; 21.2 versions prior to 21.2R1-S1, 21.2R2;
References
History
Type Values Removed Values Added
Title Junos OS: J-Web allows a locally authenticated attacker to escalate their privileges to root. Junos OS: J-Web allows a locally authenticated attacker to escalate their privileges to root.
Weaknesses

Sources

Status
PUBLISHED
Assigner
juniper
Published
Updated
Sep 16, 2024, 8:47 PM
Reserved
Apr 15, 2021, 12:00 AM
Status
Modified
Published
Oct 19, 2021, 7:15 PM
Modified
Jun 17, 2026, 3:51 AM