CVE-2024-21591
Junos OS: SRX Series and EX Series: Security Vulnerability in J-web allows a preAuth Remote Code Execution
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Junos OS: SRX Series and EX Series: Security Vulnerability in J-web allows a preAuth Remote Code Execution
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.
- Record
CVE-2024-21591- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-787
- Updated
- 2026-11-02
EUVDEUVD-2024-19239
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.
- Record
EUVD-2024-19239- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-j7xq-gvq8-pr7m
An Out-of-bounds Write vulnerability in J-Web of Juniper Networks Junos OS on SRX Series and EX...
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.
- Record
GHSA-j7xq-gvq8-pr7m- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-787
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2024-21591- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-787
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2024-21591 is a critical vulnerability (CVSS 9.8) in Juniper Junos, published January 12, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 17.7%, the 97th percentile. No source names a fixed version.