Riskcovery

CVE-2026-57023

Junos OS: MX with SPC3, SRX Series: A specifically malformed TCP packet causes a flowd crash

State
Published
Severity
8.7 High
Published
Jul 9, 2026
Updated
Jul 10, 2026
Reserved
Jun 23, 2026

Read the record on cve.org

Description

An Improper Validation of Specified Quantity in Input vulnerability in the TCP proxy plugin of Juniper Networks Junos OS on MX Series with SPC3, and SRX Series allows an unauthenticated, network-based attacker to cause a complete Denial of Service (DoS).

When TCP proxy is engaged in a flow session, to support ALGs, Advanced Anti-Malware, ICAP or UTM, a TCP packet with specifically malformed TCP header will cause flow processing daemon (flowd) to crash and restart. This causes a complete service outage until the system has automatically recovered.

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

* 23.4 versions before 23.4R2-S7,  * 24.2 versions before 24.2R2-S4,  * 24.4 versions before 24.4R2-S3, * 25.2 versions before 25.2R2.

This issue does not affect releases before 23.4R1.

Scores

CVSSScoreVectorSource
4.08.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/RE:Mjuniper
3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hjuniper

Weaknesses

  • CWE-1284 Improper Validation of Specified Quantity in Input

Affected Products

ProductVersions
Junos OSJuniper Networks
  • 23.4 to before 23.4R2-S7Affected
  • 24.2 to before 24.2R2-S4Affected
  • 24.4 to before 24.4R2-S3Affected
  • 25.2 to before 25.2R2Affected

References

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