CVE-2026-57023
Junos OS: MX with SPC3, SRX Series: A specifically malformed TCP packet causes a flowd crash
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.
INFO
Published Date :
July 9, 2026, 10:17 p.m.
Last Modified :
July 9, 2026, 10:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-57023
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 8cbe9d5a-a066-4c94-8978-4b15efeae968 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | 8cbe9d5a-a066-4c94-8978-4b15efeae968 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Junos OS on MX Series to version 23.4R2-S7 or later.
- Update Junos OS on SRX Series to version 24.2R2-S4 or later.
- Update Junos OS on SRX Series to version 24.4R2-S3 or later.
- Update Junos OS on SRX Series to version 25.2R2 or later.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-57023.
| URL | Resource |
|---|---|
| https://supportportal.juniper.net/JSA110083 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-57023 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-57023
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-57023 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-57023 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jul. 09, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Juniper Networks', 'product': 'Junos OS', 'versions': [{'status': 'affected', 'version': '23.4', 'lessThan': '23.4R2-S7', 'versionType': 'custom'}, {'status': 'affected', 'version': '24.2', 'lessThan': '24.2R2-S4', 'versionType': 'custom'}, {'status': 'affected', 'version': '24.4', 'lessThan': '24.4R2-S3', 'versionType': 'custom'}, {'status': 'affected', 'version': '25.2', 'lessThan': '25.2R2', 'versionType': 'custom'}], 'platforms': ['SRX Series', 'MX Series with SPC3'], 'defaultStatus': 'unaffected'}] Added 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:X/RE:M/U:X Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-1284 Added Reference https://supportportal.juniper.net/JSA110083