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

CVE-2024-21591 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 25.0%.

Which versions of Junos are affected by CVE-2024-21591?

CVE-2024-21591 presents critical security risk, a out-of-bounds write vulnerability rated CVSS 9.8.

Is there a public PoC exploit available for CVE-2024-21591?

Yes, a public proof-of-concept exploit is available for CVE-2024-21591. Prioritise patching immediately. EPSS: 25.0%.

How to fix or mitigate CVE-2024-21591?

Within 24 hours: Identify all affected systems and apply vendor patches immediately. If patching is delayed, consider network segmentation to limit exposure.

Junos CVE-2024-21591

CRITICAL

Out-of-bounds Write (CWE-787)

2024-01-12 sirt@juniper.net

Buffer Overflow Denial Of Service Juniper Memory Corruption RCE Junos

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:34 vuln.today

PoC Detected

May 05, 2025 - 14:11 vuln.today

Public exploit code

CVE Published

Jan 12, 2024 - 01:15 nvd

CRITICAL 9.8

DescriptionCVE.org

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.

AnalysisAI

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. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 25.0%.

Technical ContextAI

This vulnerability is classified as Out-of-bounds Write (CWE-787), which allows attackers to write data beyond allocated buffer boundaries leading to code execution or crashes. 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.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. Affected products include: Juniper Junos.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate write boundaries, use memory-safe languages, enable compiler protections (ASLR, stack canaries).