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VulnerabilityPublished Updated

CVE-2026-33780: Juniper Networks Junos OS · Memory Leak

Affects Juniper Networks Junos OSSource CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium · fixed in 24.2R2 : update Juniper Networks Junos OS when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
6.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 24.2R2, 23.4R2-S4, 23.2R2-S3 +5
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade Junos to 24.2R2, 23.4R2-S4, 23.2R2-S3 or 22.4R3-S5 (OS); 24.2R2-EVO, 23.4R2-S4-EVO, 23.2R2-S3-EVO or 22.4R3-S5-EVO (OS Evolved).

Affected software

ProductAffectedFixed in
Juniper NetworksJunos OSAffected
  • >=24.2 <24.2R2
Fixed in
  • 24.2R2
Juniper NetworksJunos OSAffected
  • >=23.4 <23.4R2-S4
Fixed in
  • 23.4R2-S4
Juniper NetworksJunos OSAffected
  • >=23.2 <23.2R2-S3
Fixed in
  • 23.2R2-S3
Juniper NetworksJunos OSAffected
  • <22.4R3-S5
Fixed in
  • 22.4R3-S5
Juniper NetworksJunos OS EvolvedAffected
  • >=23.2 <23.2R2-S3-EVO
  • >=23.4 <23.4R2-S4-EVO
  • >=24.2 <24.2R2-EVO
Fixed in
  • 24.2R2-EVO
  • 23.4R2-S4-EVO
  • 23.2R2-S3-EVO
  • 22.4R3-S5-EVO

AI-suggested

A patch is available for this vulnerability in Junos OS and Junos OS Evolved versions 22.4R3-S5 and later, including specific updates for 23.2, 23.4, and 24.2 releases. Since this is a cloud-hosted service, Juniper manages remediation server-side. Users should verify that their systems are updated to the fixed versions to prevent exploitation. Monitor memory usage of the l2ald process using the provided command to detect abnormal consumption. Check the official Juniper advisory for the latest patch and remediation details.

Description

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.

References

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