SB2026012019 - Memory leak in Junos OS Evolved and Juniper Junos OS
Published: January 20, 2026
Security Bulletin ID
SB2026012019
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Adjecent network
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Memory leak (CVE-ID: CVE-2026-21909)
CWE-ID: CWE-401 - Missing release of memory after effective lifetime
CVSSv4: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to missing release of memory after effective lifetime error in the routing protocol daemon (rpd). A remote non-authenticated attacker can send a specific update packet causing a memory leak.
Remediation
Install update from vendor's website.