CVE-2026-57021
Undergoing Analysis
Undergoing Analysis - In Progress
Out-of-bounds Write in Juniper Networks Junos OS SRX Series
Vulnerability report for CVE-2026-57021, 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 Out-of-bounds Write vulnerability in the http-gatekeeper (http-gk) of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).
If an SRX Series device is configured for remote-access VPN with pre-logon compliance check, a network-based attacker sending specifically formatted requests can trigger an out of bounds write leading to an http-gk process crash. This crash leads to unavailability of all services depending on the [ system services web-management ] configuration (like J-Web, remote access VPN and firewall authentication) until the process automatically restarts.
This issue affects Junos OS on SRX Series:
* 23.2 versions before 23.2R2-S7,
* 23.4 versions before 23.4R2-S8,
* 24.2 versions before 24.2R2-S4,
* 24.4 versions before 24.4R2-S4,
* 25.2 versions before 25.2R2,
* 25.4 versions before 25.4R1-S1, 25.4R2.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| juniper_networks | junos_os | to 23.2R2-S7 (exc) |
| juniper_networks | junos_os | to 23.4R2-S8 (exc) |
| juniper_networks | junos_os | to 24.2R2-S4 (exc) |
| juniper_networks | junos_os | to 24.4R2-S4 (exc) |
| juniper_networks | junos_os | to 25.2R2 (exc) |
| juniper_networks | junos_os | to 25.4R1-S1 (exc) |
| juniper_networks | junos_os | to 25.4R2 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-787 | The product writes data past the end, or before the beginning, of the intended buffer. |
