SB2026070874 - Denial of service in Junos OS http-gatekeeper

Security Bulletin ID SB2026070874

CSH Severity

Medium

Patch available

YES

Number of vulnerabilities 1

Exploitation vector Remote access

Highest impact Partial DoS

Breakdown by Severity

Low
Medium
High
Critical

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds write (CVE-ID: CVE-2026-57021)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to out-of-bounds write in the http-gatekeeper (http-gk) process when handling specifically formatted requests. A remote attacker can send specially crafted requests to cause a denial of service.

Only devices configured for remote-access VPN with pre-logon compliance checks are vulnerable. The crash can make services depending on web-management unavailable until the process automatically restarts.

Remediation

Install update from vendor's website.

References

https://supportportal.juniper.net/s/article/2026-07-Security-Bulletin-Junos-OS-SRX-Series-If-VPN-compliance-check-is-configured-an-attacker-can-cause-http-gk-process-crash-CVE-2026-57021