CVE-2024-39540: high-severity vulnerability in Juniper Networks Junos OS
Junos OS: SRX Series, and MX Series with SPC3: Specific valid TCP traffic can cause a pfe crash
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.7epss 0.5%
An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on SRX Series, and MX Series with SPC3 allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).
When an affected device receives specific valid TCP traffic, the pfe crashes and restarts leading to a momentary but complete service outage.
This issue affects Junos OS:
21.2 releases from 21.2R3-S5 before 21.2R3-S6.
This issue does not affect earlier or later releases.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L
Affected products
Juniper Networks · Junos OSRelated CVEs — Juniper Networks Junos OS
In the same product, most dangerous first.
CVE-2023-36845CRITICALJunos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to control an important environment variableEPSS 95.1%KEVCVE-2023-36846MEDIUMJunos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary filesEPSS 93.5%KEVCVE-2023-36844MEDIUMJunos OS: EX Series: A PHP vulnerability in J-Web allows an unauthenticated attacker to control important environment variablesEPSS 90.0%KEVCVE-2023-36847MEDIUMJunos OS: EX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary filesEPSS 83.5%KEVCVE-2020-1631HIGHOut of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) servicesEPSS 4.9%KEVCVE-2025-21590MEDIUMJunos OS: An local attacker with shell access can execute arbitrary codeEPSS 1.7%KEV