SB2026050819 - Memory leak in Junos OS and Junos OS Evolved EVPN-MPLS

Security Bulletin ID SB2026050819

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-2026-33780)

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 attacker to cause a denial of service.

The vulnerability exists due to missing release of memory after effective lifetime in the Layer 2 Address Learning Daemon (l2ald) when processing churn of ESI routes in an EVPN-MPLS scenario. A remote attacker can trigger ESI route churn to cause a denial of service.

The device must be configured for EVPN-MPLS to be exposed to this issue.

Remediation

Install update from vendor's website.

References

https://supportportal.juniper.net/s/article/2026-04-Security-Bulletin-Junos-OS-and-Junos-OS-Evolved-In-an-EVPN-MPLS-scenario-churn-of-ESI-routes-causes-a-memory-leak-in-l2ald-CVE-2026-33780