Is CVE-2024-21591 actively exploited?

No active exploitation of CVE-2024-21591 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2024-21591 be exploited remotely?

Yes. CVE-2024-21591 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2024-21591?

CVE-2024-21591 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2024-21591

CWE-787Published: January 12, 2024· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

An Out-of-bounds Write vulnerability in J-Web of Juniper Networks Junos OS on SRX Series and EX Series allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS), or Remote Code Execution (RCE) and obtain root privileges on the device.

This issue is caused by use of an insecure function allowing an attacker to overwrite arbitrary memory.

This issue affects Juniper Networks Junos OS SRX Series and EX Series:

* Junos OS versions earlier than 20.4R3-S9;

* Junos OS 21.2 versions earlier than 21.2R3-S7;

* Junos OS 21.3 versions earlier than 21.3R3-S5;

* Junos OS 21.4 versions earlier than 21.4R3-S5;

* Junos OS 22.1 versions earlier than 22.1R3-S4;

* Junos OS 22.2 versions earlier than 22.2R3-S3;

* Junos OS 22.3 versions earlier than 22.3R3-S2;

* Junos OS 22.4 versions earlier than 22.4R2-S2, 22.4R3.

NVD Source

Risk Analysis

An out-of-bounds write vulnerability in the J-Web interface of Juniper Junos OS allows unauthenticated remote attackers to achieve remote code execution or cause a denial of service. The 9.8 CVSS score underscores the critical risk to affected SRX and EX series devices.

No public exploit is known, and it is not in the CISA KEV. The vulnerability is remotely exploitable with low attack complexity.

Recommended Action

Upgrade Junos OS to the recommended patched versions provided by Juniper. Disable the J-Web interface if it is not required for device management.

Generated by the CTIWATCH analysis pipeline from this CVE's metadata (CVSS, EPSS, KEV status, exploit intelligence). Verify against vendor advisories before acting.

Technical Analysis

CVE-2024-21591 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-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.