Is CVE-2021-31349 actively exploited?

No active exploitation of CVE-2021-31349 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-31349 be exploited remotely?

Yes. CVE-2021-31349 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-31349?

CVE-2021-31349 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2021-31349

CWE-287Published: October 19, 2021· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

The usage of an internal HTTP header created an authentication bypass vulnerability (CWE-287), allowing an attacker to view internal files, change settings, manipulate services and execute arbitrary code. This issue affects all Juniper Networks 128 Technology Session Smart Router versions prior to 4.5.11, and all versions of 5.0 up to and including 5.0.1.

NVD Source

Technical Analysis

CVE-2021-31349 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

From a weakness classification perspective (CWE-287): Authentication bypass vulnerabilities allow attackers to access protected resources without valid credentials.