CVE-2024-21591 | Junos OS: SRX Series and EX Series: Security Vulnerability in J-web allows a preAuth Remote Code Execution

Exp

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.

Published: 2024-01-11 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-21591 is rated High Exploit Risk (88.2/100): CVSS Critical severity, with high exploitation likelihood (EPSS 17.67%, 97th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2024-21591

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2024-21591

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-23 17.53% 17.67% +0.14%
2 2026-06-15 16.70% 17.53% +0.84%
3 2026-05-20 — 16.70% —

Full EPSS history (20 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-21591

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]

Weakness enumeration for CVE-2024-21591

Affected software / configurations for CVE-2024-21591

Vendor Product Version Raw CPE
juniper junos < 20.4 cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:-:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r1:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r1-s1:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r2:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r2-s1:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r2-s2:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s1:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s2:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s3:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s4:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s5:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s6:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s7:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s8:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:-:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r1:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r1-s1:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r1-s2:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r2:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r2-s1:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r2-s2:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s1:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s2:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s3:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s4:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s5:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s6:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:-:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r1:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r1-s1:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r1-s2:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r2:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r2-s1:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r2-s2:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r3:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r3-s1:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r3-s2:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r3-s3:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r3-s4:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:-:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r1:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r1-s1:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r1-s2:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r2:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r2-s1:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r2-s2:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r3:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r3-s1:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r3-s2:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r3-s3:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r3-s4:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:-:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r1:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r1-s1:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r1-s2:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r2:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r2-s1:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r2-s2:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r3:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r3-s1:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r3-s2:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r3-s3:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:-:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r1:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r1-s1:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r1-s2:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r2:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r2-s1:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r2-s2:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r3:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r3-s1:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r3-s2:*:*:*:*:*:*
juniper junos 22.3 cpe:2.3:o:juniper:junos:22.3:-:*:*:*:*:*:*
juniper junos 22.3 cpe:2.3:o:juniper:junos:22.3:r1:*:*:*:*:*:*
juniper junos 22.3 cpe:2.3:o:juniper:junos:22.3:r1-s1:*:*:*:*:*:*
juniper junos 22.3 cpe:2.3:o:juniper:junos:22.3:r1-s2:*:*:*:*:*:*
juniper junos 22.3 cpe:2.3:o:juniper:junos:22.3:r2:*:*:*:*:*:*

References for CVE-2024-21591

cvelogic Threat Intelligence