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CVE-2026-57026 Juniper Networks CVE debrief

CVE-2026-57026 is an Improper Validation of Syntactic Correctness of Input vulnerability in the SIP plugin of Juniper Networks Junos OS on MX Series with SPC3 and SRX Series. This issue allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS) by processing a malformed SIP invite packet, leading to a flow processing daemon (flowd) crash and restart, resulting in a complete service outage until the system automatically recovers.

Vendor
Juniper Networks
Product
Junos OS
CVSS
HIGH 8.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-09
Original CVE updated
2026-07-10
Advisory published
2026-07-09
Advisory updated
2026-07-10

Who should care

Security teams and administrators responsible for Juniper Networks Junos OS on MX Series with SPC3 and SRX Series should prioritize patching, as this vulnerability allows for a Denial-of-Service (DoS) attack.

Technical summary

The vulnerability exists in the SIP plugin of Juniper Networks Junos OS on MX Series with SPC3 and SRX Series. An unauthenticated, network-based attacker can exploit this by sending a malformed SIP invite packet, which causes the flow processing daemon (flowd) to crash and restart. This results in a complete service outage until the system automatically recovers. 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.

Defensive priority

High priority should be given to patching Juniper Networks Junos OS on MX Series with SPC3 and SRX Series due to the high CVSS score of 8.7 and the potential for Denial-of-Service (DoS) attacks.

Recommended defensive actions

  • Apply patches for affected Juniper Networks Junos OS versions on MX Series with SPC3 and SRX Series.
  • Disable SIP ALG if not required.
  • Monitor for suspicious SIP traffic.
  • Implement compensating controls such as rate limiting for SIP traffic.
  • Verify system configurations and inventory for affected systems.

Evidence notes

The CVE record was published on 2026-07-09T22:17:07.923Z and was last modified on 2026-07-10T15:16:45.013Z. The NVD entry is currently Received. Limited details are available about the specific conditions and vectors of the vulnerability, emphasizing the need for patching and monitoring.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-57026 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-57026

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-57026 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-57026

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.