High7.5Juniper Networks

High [CVE-2026-57026] 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 allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).If the SIP ALG is enabled on an affected device, the processing of a malformed SIP invite packet will cause a flow processing daemon (flowd) crash and restart

This high-severity Juniper Networks advisory covers CVE-2026-57026 affecting Junos OS, Junos, SRX.

CVE-2026-57026 Published Jul 9, 2026Updated by vendor Jul 14, 2026

CVE-2026-57026

Affected products & platforms

Juniper NetworksSRXFirewallRoutersJunosMX / Routers

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Summary

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 allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).If the SIP ALG is enabled on an affected device, the processing of a malformed SIP invite packet will cause a flow processing daemon (flowd) crash and restart.

This leads to a complete service outage until the system has automatically recovered.

This issue affects Junos OS on MX Series with SPC3 and SRX Series:

all versions before 23.2R2-S7,
23.4 versions before 23.4R2-S8,
25.4 versions before 25.4R1-S2.

Affected products named by the advisory: MX.

Affected versions

* all versions before 23

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Fixed versions

23.2R2-S7
23.4R2-S8
24.2R2-S5
24.4R2-S4
25.2R2
25.4R1-S2

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Mitigation

Upgrade to a fixed release: 23.2R2-S7, 23.4R2-S8, 24.2R2-S5, 24.4R2-S4, 25.2R2, 25.4R1-S2. That is the remediation for this advisory.

The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Sources

Official and corroborating records used to build this advisory.

NVD discovery recordNVD
Independent discovery and scoring cross-reference. Vendor remediation guidance takes precedence. Discovered from the machine-readable feed https://services.nvd.nist.gov/rest/json/cves/2.0; this link opens the NVD record for CVE-2026-57026 instead of the raw feed document.
NIST National Vulnerability Database

Cross-references

Validate CVE metadata against the authoritative registries.

CVE-2026-57026NVD CVE.org MITRE

Official resources

Junos OS software downloads & install/upgrade (target: 23.2R2-S7 / 23.4R2-S8 / 24.2R2-S5)
Official documentation
This advisory names 23.2R2-S7 / 23.4R2-S8 / 24.2R2-S5 as the first fixed releases — official upgrade documentation for Junos OS on SRX / MX / EX / QFX.
Junos OS release & EOL / support dates
Release notes
Confirm your train is still supported and pick a fixed maintenance release.
Juniper Security Advisories portal
Official documentation
Canonical Juniper SIRT advisory portal — search here for the full JSA text and revisions.

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