CVE intelligence and bounded remediation

CVE-2026-33780 — Juniper Junos security vulnerability

High CVSS 7.1

A Missing Release of Memory after Effective Lifetime vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause a memory leak ultimately leading to a Denial of Service (DoS). In an EVPN-MPLS scenario, routes learned from remote multi-homed Provider Edge (PE) devices are programmed as ESI routes. Due to a logic issue in the l2ald memory management, memory allocated for these routes is not released when there is churn for these routes. As a result, memory leaks in the l2ald process which will ultimately lead to a crash and restart of l2ald. Use the following command to monitor the memory consumption by l2ald: user@device> show system process extensive | match "PID|l2ald" This issue affects: Junos OS: * all versions before 22.4R3-S5, * 23.2 versions before 23.2R2-S3, * 23.4 versions before 23.4R2-S4, * 24.2 versions before 24.2R2; Junos OS Evolved: * all versions before 22.4R3-S5-EVO, * 23.2 versions before 23.2R2-S3-EVO, * 23.4 versions before 23.4R2-S4-EVO, * 24.2 versions before 24.2R2-EVO.

Severity
High
CVSS
7.1 (4.0)
Published
2026-04-09
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-401

Affected products

  • juniper / junos
  • juniper / junos / 22.4

Showing 2 representative product identities from 63 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Resource exhaustion and denial of service

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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