CVE-2026-57022: CWE-754 Improper Check for Unusual or Exceptional Conditions in Juniper Networks Junos OS
An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX with SPC3 and SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). When an affected device initiates a TCP connection to an attacker-controlled system that responds with a specific packet, this causes a PFE crash and restart, which affects all services until the system has automatically recovered. This issue can happen among others in the following scenarios: ALG, SSL proxy, UTM, RTLOG, AppQoE probing, AAMW, ICAP, URL filtering. This issue affects Junos OS on MX Series with SPC3, SRX5k Series with SPC3, SRX1600 Series, SRX2300 Series, SRX4000 Series, and vSRX Series: * all versions before 23.2R2-S4, * 23.4 versions before 23.4R2-S5, * 24.2 versions before 24.2R2.
AI Analysis
Technical Summary
This vulnerability (CVE-2026-57022) in Juniper Junos OS Packet Forwarding Engine (PFE) is due to improper checking of unusual or exceptional conditions. An unauthenticated network attacker can cause a denial of service by responding with a specific packet to a TCP connection initiated by the affected device, causing the PFE to crash and restart. The impact is a temporary service disruption until automatic recovery completes. The vulnerability affects multiple Junos OS platforms and versions prior to the specified fixed releases.
Potential Impact
An unauthenticated, network-based attacker can cause a denial of service by triggering a PFE crash and restart on affected Junos OS devices. This results in temporary disruption of all services until the system automatically recovers. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The vulnerability affects versions before 23.2R2-S4, 23.4 versions before 23.4R2-S5, and 24.2 versions before 24.2R2. Administrators should monitor Juniper Networks advisories for official patches or updates addressing this issue. Until a patch is applied, consider minimizing unnecessary TCP connections to attacker-controlled systems and review network policies to reduce exposure to potentially malicious responses.
CVE-2026-57022: CWE-754 Improper Check for Unusual or Exceptional Conditions in Juniper Networks Junos OS
Description
An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX with SPC3 and SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). When an affected device initiates a TCP connection to an attacker-controlled system that responds with a specific packet, this causes a PFE crash and restart, which affects all services until the system has automatically recovered. This issue can happen among others in the following scenarios: ALG, SSL proxy, UTM, RTLOG, AppQoE probing, AAMW, ICAP, URL filtering. This issue affects Junos OS on MX Series with SPC3, SRX5k Series with SPC3, SRX1600 Series, SRX2300 Series, SRX4000 Series, and vSRX Series: * all versions before 23.2R2-S4, * 23.4 versions before 23.4R2-S5, * 24.2 versions before 24.2R2.
CVSS v3.1
Score 5.9medium
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-57022) in Juniper Junos OS Packet Forwarding Engine (PFE) is due to improper checking of unusual or exceptional conditions. An unauthenticated network attacker can cause a denial of service by responding with a specific packet to a TCP connection initiated by the affected device, causing the PFE to crash and restart. The impact is a temporary service disruption until automatic recovery completes. The vulnerability affects multiple Junos OS platforms and versions prior to the specified fixed releases.
Potential Impact
An unauthenticated, network-based attacker can cause a denial of service by triggering a PFE crash and restart on affected Junos OS devices. This results in temporary disruption of all services until the system automatically recovers. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The vulnerability affects versions before 23.2R2-S4, 23.4 versions before 23.4R2-S5, and 24.2 versions before 24.2R2. Administrators should monitor Juniper Networks advisories for official patches or updates addressing this issue. Until a patch is applied, consider minimizing unnecessary TCP connections to attacker-controlled systems and review network policies to reduce exposure to potentially malicious responses.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- juniper
- Date Reserved
- 2026-06-23T16:27:00.248Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a50171668715ace431ea1f3
Added to database: 07/09/2026, 21:48:06 UTC
Last enriched: 07/17/2026, 09:54:33 UTC
Last updated: 08/22/2026, 22:52:14 UTC
Views: 59
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