CVE-2026-57023
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TCP Proxy Plugin DoS in Juniper Junos OS
Vulnerability report for CVE-2026-57023, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-07-09
Last updated on: 2026-07-10
Assigner: Juniper Networks, Inc.
Description
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.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| juniper_networks | junos_os | to 23.4R2-S7 (exc) |
| juniper_networks | junos_os | to 24.2R2-S4 (exc) |
| juniper_networks | junos_os | to 24.4R2-S3 (exc) |
| juniper_networks | junos_os | to 25.2R2 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-1284 | The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties. |
