CVE-2026-57026: CWE-1286 Improper Validation of Syntactic Correctness of Input in Juniper Networks Junos OS
CVE-2026-57026 is a vulnerability in Juniper Networks Junos OS affecting MX Series with SPC3 and SRX Series devices. It involves improper validation of syntactic correctness of input in the SIP plugin. When SIP ALG is enabled, processing a malformed SIP invite packet can cause the flow processing daemon (flowd) to crash and restart, resulting in a denial-of-service (DoS) condition and temporary service outage until automatic recovery occurs. This affects multiple Junos OS versions prior to specific patch releases.
AI Analysis
Technical Summary
This vulnerability (CVE-2026-57026) is due to improper validation of syntactic correctness of input in the SIP plugin of Juniper Networks Junos OS on MX Series with SPC3 and SRX Series devices. An unauthenticated, network-based attacker can send a malformed SIP invite packet when SIP ALG is enabled, causing the flow processing daemon (flowd) to crash and restart. This leads to a denial-of-service condition causing complete service outage until the system recovers automatically. The affected versions include all versions before 23.2R2-S7, 23.4 versions before 23.4R2-S8, 24.2 versions before 24.2R2-S5, 24.4 versions before 24.4R2-S4, 25.2 versions before 25.2R2, and 25.4 versions before 25.4R1-S2.
Potential Impact
The impact of this vulnerability is a denial-of-service (DoS) condition resulting from the crash and restart of the flow processing daemon (flowd) on affected Junos OS devices. This causes a complete service outage until the system automatically recovers. There is no impact on confidentiality or integrity reported. The vulnerability can be exploited remotely without authentication.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until patches are confirmed and applied, consider disabling SIP ALG if feasible to mitigate the risk of flowd crashes caused by malformed SIP invite packets. Monitor vendor communications for official fixes and apply updates promptly once available.
CVE-2026-57026: CWE-1286 Improper Validation of Syntactic Correctness of Input in Juniper Networks Junos OS
Description
CVE-2026-57026 is a vulnerability in Juniper Networks Junos OS affecting MX Series with SPC3 and SRX Series devices. It involves improper validation of syntactic correctness of input in the SIP plugin. When SIP ALG is enabled, processing a malformed SIP invite packet can cause the flow processing daemon (flowd) to crash and restart, resulting in a denial-of-service (DoS) condition and temporary service outage until automatic recovery occurs. This affects multiple Junos OS versions prior to specific patch releases.
CVSS v3.1
Score 7.5high
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-57026) is due to improper validation of syntactic correctness of input in the SIP plugin of Juniper Networks Junos OS on MX Series with SPC3 and SRX Series devices. An unauthenticated, network-based attacker can send a malformed SIP invite packet when SIP ALG is enabled, causing the flow processing daemon (flowd) to crash and restart. This leads to a denial-of-service condition causing complete service outage until the system recovers automatically. The affected versions include all versions before 23.2R2-S7, 23.4 versions before 23.4R2-S8, 24.2 versions before 24.2R2-S5, 24.4 versions before 24.4R2-S4, 25.2 versions before 25.2R2, and 25.4 versions before 25.4R1-S2.
Potential Impact
The impact of this vulnerability is a denial-of-service (DoS) condition resulting from the crash and restart of the flow processing daemon (flowd) on affected Junos OS devices. This causes a complete service outage until the system automatically recovers. There is no impact on confidentiality or integrity reported. The vulnerability can be exploited remotely without authentication.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until patches are confirmed and applied, consider disabling SIP ALG if feasible to mitigate the risk of flowd crashes caused by malformed SIP invite packets. Monitor vendor communications for official fixes and apply updates promptly once available.
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: 6a50171668715ace431ea1ff
Added to database: 07/09/2026, 21:48:06 UTC
Last enriched: 07/09/2026, 22:02:45 UTC
Last updated: 07/10/2026, 03:46:08 UTC
Views: 7
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