CVE-2024-39529Network attack vector

PFE crash via externally controlled format string

Published Jul 11, 2024 · Updated Aug 2, 2024

Use of an externally controlled format string in Juniper Networks Junos OS on SRX Series allows remote attackers to crash and restart the PFE. Within the PFE, data reached through specific valid transit DNS traffic is used as a format string; Juniper has not identified the routine or DNS field. DGA or tunnel detection and DNS-filtering traceoptions must both be configured, and exploitation interrupts forwarding while the PFE restarts.

CVSS severity8.7
High
EPSS probability0.48%
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

Use of an externally controlled format string in Juniper Networks Junos OS on SRX Series allows remote attackers to crash and restart the PFE. Within the PFE, data reached through specific valid transit DNS traffic is used as a format string; Juniper has not identified the routine or DNS field. DGA or tunnel detection and DNS-filtering traceoptions must both be configured, and exploitation interrupts forwarding while the PFE restarts.

The record

CVE
CVE-2024-39529
Published
Jul 11, 2024
Updated
Aug 2, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-134, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 11, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 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 <21.4r3-s6
  2. Affected versionversion=0 <21.4R3-S6
  3. Affected versionversion=22.2 <22.2r3-s3
  4. Affected versionversion=22.2 <22.2R3-S3
  5. Affected versionversion=22.3 <22.3r3-s3
  6. Affected versionversion=22.3 <22.3R3-S3
  7. Affected versionversion=22.4 <22.4r3
  8. Affected versionversion=22.4 <22.4R3
  9. Affected versionversion=23.2 <23.2r2
  10. Affected versionversion=23.2 <23.2R2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=0 <21.4r3-s6; version=0 <21.4R3-S6; version=22.2 <22.2r3-s3; version=22.2 <22.2R3-S3; version=22.3 <22.3r3-s3; version=22.3 <22.3R3-S3; version=22.4 <22.4r3; version=22.4 <22.4R3; version=23.2 <23.2r2; version=23.2 <23.2R2

Published CVSS scores

7.5Juniper NetworksCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7Juniper NetworksCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-134Use of Externally-Controlled Format String
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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