CVE-2024-21591Public exploitNetwork attack vector

Root code execution via out-of-bounds memory write

Published Jan 12, 2024 · Updated Oct 25, 2024

Out-of-bounds writing in J-Web in Juniper Networks Junos OS on SRX and EX Series allows remote attackers to execute code as root. An insecure function processes network input without adequate bounds enforcement and overwrites arbitrary memory; Juniper has not named the function. J-Web must be enabled over HTTP or HTTPS; no authentication or user interaction is required, and exploitation can instead crash the device.

CVSS severity9.8
Critical
EPSS probability17.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds writing in J-Web in Juniper Networks Junos OS on SRX and EX Series allows remote attackers to execute code as root. An insecure function processes network input without adequate bounds enforcement and overwrites arbitrary memory; Juniper has not named the function. J-Web must be enabled over HTTP or HTTPS; no authentication or user interaction is required, and exploitation can instead crash the device.

The record

CVE
CVE-2024-21591
Published
Jan 12, 2024
Updated
Oct 25, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-787, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 12, 2024CVE publishedPublication date reported by the CVE source.
  2. Oct 25, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <20.4R3-S9
  2. Affected versionversion=21.2 <21.2R3-S7
  3. Affected versionversion=21.3 <21.3R3-S5
  4. Affected versionversion=21.4 <21.4R3-S5
  5. Affected versionversion=22.1 <22.1R3-S4
  6. Affected versionversion=22.2 <22.2R3-S3
  7. Affected versionversion=22.3 <22.3R3-S2
  8. Affected versionversion=22.4 <22.4R2-S2, 22.4R3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=0 <20.4R3-S9; version=21.2 <21.2R3-S7; version=21.3 <21.3R3-S5; version=21.4 <21.4R3-S5; version=22.1 <22.1R3-S4; version=22.2 <22.2R3-S3; version=22.3 <22.3R3-S2; version=22.4 <22.4R2-S2, 22.4R3

Published CVSS scores

9.8Juniper NetworksCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo