An Improper Handling of Exceptional Conditions vulnerability in packet processing of Juniper Networks Junos OS on MX Series with MPC10/MPC11/LC9600 line cards, EX9200 with EX9200-15C lines cards, MX304 devices, and Juniper Networks Junos OS Evolved on PTX Series, allows an attacker sending malformed DHCP packets to cause ingress packet processing to stop, leading to a Denial of Service (DoS). Continued receipt and processing of these packets will create a sustained Denial of Service (DoS) condition.
This issue only occurs if DHCP snooping is enabled. See configuration below.
This issue can be detected using following commands. Their output will display the interface status going down:
user@device>show interfaces <if--x/x/x> user@device>show log messages | match <if--x/x/x> user@device>show log messages ==> will display the "[Error] Wedge-Detect : Host Loopback Wedge Detected: PFE: no," logs.
This issue affects: Junos OS on
MX Series
with MPC10/MPC11/LC9600 line cards, EX9200 with EX9200-15C line cards, and MX304:
Junos OS Evolved on PTX Series:
from 19.3R1-EVO before 21.2R3-S8-EVO,
from 21.4-EVO before 21.4R3-S7-EVO,
from 22.1-EVO before 22.1R3-S6-EVO,
from 22.2-EVO before 22.2R3-S5-EVO,
from 22.3-EVO before 22.3R3-S3-EVO,
from 22.4-EVO before 22.4R3-S1-EVO,
from 23.2-EVO before 23.2R2-S2-EVO,
from 23.4-EVO before 23.4R2-EVO.
Junos OS Evolved releases prior to 19.3R1-EVO are unaffected by this vulnerability
| Software | From | Fixed in |
|---|---|---|
| juniper / junos | - | 21.2 |
| juniper / junos | 21.2 | 21.2.x |
| juniper / junos | 21.2-r1 | 21.2-r1.x |
| juniper / junos | 21.2-r1-s1 | 21.2-r1-s1.x |
| juniper / junos | 21.2-r1-s2 | 21.2-r1-s2.x |
| juniper / junos | 21.2-r2 | 21.2-r2.x |
| juniper / junos | 21.2-r2-s1 | 21.2-r2-s1.x |
| juniper / junos | 21.2-r2-s2 | 21.2-r2-s2.x |
| juniper / junos | 21.2-r3 | 21.2-r3.x |
| juniper / junos | 21.2-r3-s1 | 21.2-r3-s1.x |
| juniper / junos | 21.2-r3-s2 | 21.2-r3-s2.x |
| juniper / junos | 21.2-r3-s3 | 21.2-r3-s3.x |
| juniper / junos | 21.2-r3-s4 | 21.2-r3-s4.x |
| juniper / junos | 21.2-r3-s5 | 21.2-r3-s5.x |
| juniper / junos | 21.2-r3-s6 | 21.2-r3-s6.x |
| juniper / junos | 21.4 | 21.4.x |
| juniper / junos | 21.4-r1 | 21.4-r1.x |
| juniper / junos | 21.4-r1-s1 | 21.4-r1-s1.x |
| juniper / junos | 21.4-r1-s2 | 21.4-r1-s2.x |
| juniper / junos | 21.4-r2 | 21.4-r2.x |
| juniper / junos | 21.4-r2-s1 | 21.4-r2-s1.x |
| juniper / junos | 21.4-r2-s2 | 21.4-r2-s2.x |
| juniper / junos | 21.4-r3 | 21.4-r3.x |
| juniper / junos | 21.4-r3-s1 | 21.4-r3-s1.x |
| juniper / junos | 21.4-r3-s10 | 21.4-r3-s10.x |
| juniper / junos | 21.4-r3-s11 | 21.4-r3-s11.x |
| juniper / junos | 21.4-r3-s12 | 21.4-r3-s12.x |
| juniper / junos | 21.4-r3-s2 | 21.4-r3-s2.x |
| juniper / junos | 21.4-r3-s3 | 21.4-r3-s3.x |
| juniper / junos | 21.4-r3-s4 | 21.4-r3-s4.x |
| juniper / junos | 21.4-r3-s5 | 21.4-r3-s5.x |
| juniper / junos | 22.2 | 22.2.x |
| juniper / junos | 22.2-r1 | 22.2-r1.x |
| juniper / junos | 22.2-r1-s1 | 22.2-r1-s1.x |
| juniper / junos | 22.2-r1-s2 | 22.2-r1-s2.x |
| juniper / junos | 22.2-r2 | 22.2-r2.x |
| juniper / junos | 22.2-r2-s1 | 22.2-r2-s1.x |
| juniper / junos | 22.2-r2-s2 | 22.2-r2-s2.x |
| juniper / junos | 22.2-r3 | 22.2-r3.x |
| juniper / junos | 22.2-r3-s1 | 22.2-r3-s1.x |
| juniper / junos | 22.2-r3-s2 | 22.2-r3-s2.x |
| juniper / junos | 22.2-r3-s3 | 22.2-r3-s3.x |
| juniper / junos | 22.3 | 22.3.x |
| juniper / junos | 22.4 | 22.4.x |
| juniper / junos | 22.4-r1 | 22.4-r1.x |
| juniper / junos | 22.4-r1-s1 | 22.4-r1-s1.x |
| juniper / junos | 22.4-r1-s2 | 22.4-r1-s2.x |
| juniper / junos | 22.4-r2 | 22.4-r2.x |
| juniper / junos | 22.4-r2-s1 | 22.4-r2-s1.x |
| juniper / junos | 22.4-r2-s2 | 22.4-r2-s2.x |
| juniper / junos | 23.2 | 23.2.x |
| juniper / junos | 23.2-r1 | 23.2-r1.x |
| juniper / junos | 23.2-r1-s1 | 23.2-r1-s1.x |
| juniper / junos | 23.2-r1-s2 | 23.2-r1-s2.x |
| juniper / junos_os_evolved | 19.4 | 21.2 |
| juniper / junos_os_evolved | 19.3-r1 | 19.3-r1.x |
| juniper / junos_os_evolved | 19.3-r2 | 19.3-r2.x |
| juniper / junos_os_evolved | 21.2 | 21.2.x |
| juniper / junos_os_evolved | 21.2-r1 | 21.2-r1.x |
| juniper / junos_os_evolved | 21.2-r1-s1 | 21.2-r1-s1.x |
| juniper / junos_os_evolved | 21.2-r1-s2 | 21.2-r1-s2.x |
| juniper / junos_os_evolved | 21.2-r2 | 21.2-r2.x |
| juniper / junos_os_evolved | 21.2-r2-s1 | 21.2-r2-s1.x |
| juniper / junos_os_evolved | 21.2-r2-s2 | 21.2-r2-s2.x |
| juniper / junos_os_evolved | 21.2-r3 | 21.2-r3.x |
| juniper / junos_os_evolved | 21.2-r3-s1 | 21.2-r3-s1.x |
| juniper / junos_os_evolved | 21.2-r3-s2 | 21.2-r3-s2.x |
| juniper / junos_os_evolved | 21.2-r3-s3 | 21.2-r3-s3.x |
| juniper / junos_os_evolved | 21.2-r3-s4 | 21.2-r3-s4.x |
| juniper / junos_os_evolved | 21.2-r3-s5 | 21.2-r3-s5.x |
| juniper / junos_os_evolved | 21.2-r3-s6 | 21.2-r3-s6.x |
| juniper / junos_os_evolved | 21.2-r3-s7 | 21.2-r3-s7.x |
| juniper / junos_os_evolved | 21.4 | 21.4.x |
| juniper / junos_os_evolved | 21.4-r1 | 21.4-r1.x |
| juniper / junos_os_evolved | 21.4-r1-s1 | 21.4-r1-s1.x |
| juniper / junos_os_evolved | 21.4-r1-s2 | 21.4-r1-s2.x |
| juniper / junos_os_evolved | 21.4-r2 | 21.4-r2.x |
| juniper / junos_os_evolved | 21.4-r2-s1 | 21.4-r2-s1.x |
| juniper / junos_os_evolved | 21.4-r2-s2 | 21.4-r2-s2.x |
| juniper / junos_os_evolved | 21.4-r3 | 21.4-r3.x |
| juniper / junos_os_evolved | 21.4-r3-s1 | 21.4-r3-s1.x |
| juniper / junos_os_evolved | 21.4-r3-s2 | 21.4-r3-s2.x |
| juniper / junos_os_evolved | 21.4-r3-s3 | 21.4-r3-s3.x |
| juniper / junos_os_evolved | 21.4-r3-s4 | 21.4-r3-s4.x |
| juniper / junos_os_evolved | 21.4-r3-s5 | 21.4-r3-s5.x |
| juniper / junos_os_evolved | 21.4-r3-s6 | 21.4-r3-s6.x |
| juniper / junos_os_evolved | 22.1 | 22.1.x |
| juniper / junos_os_evolved | 22.1-r1 | 22.1-r1.x |
| juniper / junos_os_evolved | 22.1-r1-s1 | 22.1-r1-s1.x |
| juniper / junos_os_evolved | 22.1-r1-s2 | 22.1-r1-s2.x |
| juniper / junos_os_evolved | 22.1-r2 | 22.1-r2.x |
| juniper / junos_os_evolved | 22.1-r2-s1 | 22.1-r2-s1.x |
| juniper / junos_os_evolved | 22.1-r3 | 22.1-r3.x |
| juniper / junos_os_evolved | 22.1-r3-s1 | 22.1-r3-s1.x |
| juniper / junos_os_evolved | 22.1-r3-s2 | 22.1-r3-s2.x |
| juniper / junos_os_evolved | 22.1-r3-s3 | 22.1-r3-s3.x |
| juniper / junos_os_evolved | 22.1-r3-s4 | 22.1-r3-s4.x |
| juniper / junos_os_evolved | 22.1-r3-s5 | 22.1-r3-s5.x |
| juniper / junos_os_evolved | 22.2 | 22.2.x |
| juniper / junos_os_evolved | 22.2-r1 | 22.2-r1.x |
| juniper / junos_os_evolved | 22.2-r1-s1 | 22.2-r1-s1.x |
| juniper / junos_os_evolved | 22.2-r1-s2 | 22.2-r1-s2.x |
| juniper / junos_os_evolved | 22.2-r2 | 22.2-r2.x |
| juniper / junos_os_evolved | 22.2-r2-s1 | 22.2-r2-s1.x |
| juniper / junos_os_evolved | 22.2-r2-s2 | 22.2-r2-s2.x |
| juniper / junos_os_evolved | 22.2-r3 | 22.2-r3.x |
| juniper / junos_os_evolved | 22.2-r3-s1 | 22.2-r3-s1.x |
| juniper / junos_os_evolved | 22.2-r3-s2 | 22.2-r3-s2.x |
| juniper / junos_os_evolved | 22.2-r3-s3 | 22.2-r3-s3.x |
| juniper / junos_os_evolved | 22.2-r3-s4 | 22.2-r3-s4.x |
| juniper / junos_os_evolved | 22.3 | 22.3.x |
| juniper / junos_os_evolved | 22.3-r1 | 22.3-r1.x |
| juniper / junos_os_evolved | 22.3-r1-s1 | 22.3-r1-s1.x |
| juniper / junos_os_evolved | 22.3-r1-s2 | 22.3-r1-s2.x |
| juniper / junos_os_evolved | 22.3-r2 | 22.3-r2.x |
| juniper / junos_os_evolved | 22.3-r2-s1 | 22.3-r2-s1.x |
| juniper / junos_os_evolved | 22.3-r2-s2 | 22.3-r2-s2.x |
| juniper / junos_os_evolved | 22.3-r3 | 22.3-r3.x |
| juniper / junos_os_evolved | 22.3-r3-s1 | 22.3-r3-s1.x |
| juniper / junos_os_evolved | 22.3-r3-s2 | 22.3-r3-s2.x |
| juniper / junos_os_evolved | 22.4 | 22.4.x |
| juniper / junos_os_evolved | 22.4-r1 | 22.4-r1.x |
| juniper / junos_os_evolved | 22.4-r1-s1 | 22.4-r1-s1.x |
| juniper / junos_os_evolved | 22.4-r1-s2 | 22.4-r1-s2.x |
| juniper / junos_os_evolved | 22.4-r2 | 22.4-r2.x |
| juniper / junos_os_evolved | 22.4-r2-s1 | 22.4-r2-s1.x |
| juniper / junos_os_evolved | 22.4-r2-s2 | 22.4-r2-s2.x |
| juniper / junos_os_evolved | 22.4-r3 | 22.4-r3.x |
| juniper / junos_os_evolved | 23.2 | 23.2.x |
| juniper / junos_os_evolved | 23.2-r1 | 23.2-r1.x |
| juniper / junos_os_evolved | 23.2-r1-s1 | 23.2-r1-s1.x |
| juniper / junos_os_evolved | 23.2-r1-s2 | 23.2-r1-s2.x |
| juniper / junos_os_evolved | 23.2-r2 | 23.2-r2.x |
| juniper / junos_os_evolved | 23.2-r2-s1 | 23.2-r2-s1.x |
| juniper / junos_os_evolved | 23.4 | 23.4.x |
| juniper / junos_os_evolved | 23.4-r1 | 23.4-r1.x |
| juniper / junos_os_evolved | 23.4-r1-s1 | 23.4-r1-s1.x |
| juniper / junos_os_evolved | 23.4-r1-s2 | 23.4-r1-s2.x |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.