CVE-2026-33780 (GCVE-0-2026-33780)

Vulnerability from cvelistv5 – Published: 2026-04-09 21:29 – Updated: 2026-04-09 21:29
VLAI?
Title
Junos OS and Junos OS Evolved: In an EVPN-MPLS scenario churn of ESI routes causes a memory leak in l2ald
Summary
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 ?
6.5 (Medium)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.1 (High)
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/RE:M
CWE
  • CWE-401 - Missing Release of Memory after Effective Lifetime
Assigner
References
Impacted products
Vendor Product Version
Juniper Networks Junos OS Affected: 0 , < 22.4R3-S5 (semver)
Affected: 23.2 , < 23.2R2-S3 (semver)
Affected: 23.4 , < 23.4R2-S4 (semver)
Affected: 24.2 , < 24.2R2 (semver)
Create a notification for this product.
    Juniper Networks Junos OS Evolved Affected: all version prior to , < 22.4R3-S5-EVO (semver)
Affected: 23.2 , < 23.2R2-S3-EVO (semver)
Affected: 23.4 , < 23.4R2-S4-EVO (semver)
Affected: 24.2 , < 24.2R2-EVO (semver)
Create a notification for this product.
Date Public ?
2026-04-08 16:00
Show details on NVD website
To clipboard 

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              "value": "\u003cspan style=\"background-color: rgb(251, 251, 251);\"\u003eTo be exposed to this issue the device must be configured for EVPN-MPLS. Refer to product documentation for how to configure EVPN-MPLS as there are different configuration options.\u003c/span\u003e\n\n\u003cbr\u003e"
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              "value": "A Missing Release of Memory after Effective Lifetime vulnerability in the\u0026nbsp;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).\u003cbr\u003e\u003cbr\u003e\n\nIn 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.\u003cbr\u003e\u003cbr\u003eUse the following command to monitor the memory consumption by l2ald:\u003cbr\u003e\u003cbr\u003e\u003ctt\u003euser@device\u0026gt; show system process extensive | match \"PID|l2ald\"\u003c/tt\u003e \n\n\u003cbr\u003e\u003cbr\u003e\u003cp\u003eThis issue affects:\u003c/p\u003e\u003cp\u003eJunos OS:\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cul\u003e\u003cli\u003eall versions before 22.4R3-S5,\u003c/li\u003e\u003cli\u003e23.2 versions before 23.2R2-S3,\u003c/li\u003e\u003cli\u003e23.4 versions before 23.4R2-S4,\u003c/li\u003e\u003cli\u003e24.2 versions before 24.2R2;\u003c/li\u003e\u003c/ul\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eJunos OS Evolved:\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cul\u003e\u003cli\u003eall versions before 22.4R3-S5-EVO,\u003c/li\u003e\u003cli\u003e23.2 versions before 23.2R2-S3-EVO,\u003c/li\u003e\u003cli\u003e23.4 versions before 23.4R2-S4-EVO,\u003c/li\u003e\u003cli\u003e24.2 versions before 24.2R2-EVO.\u003c/li\u003e\u003c/ul\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"
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}


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Sightings

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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