CVE-2024-39557

Device crash via MAC-update memory leak

Published Jul 10, 2024 · Updated Aug 2, 2024

Uncontrolled resource consumption in Junos OS Evolved l2ald allows remote attackers on an adjacent network to crash and restart devices. Certain MAC table updates cause l2ald to retain small allocations for L2Rtinfo and NHOpaqueTlv objects instead of releasing them, steadily consuming system memory. No authentication or user interaction is required, but the attacker must share an adjacent network and repeat the triggering updates until memory exhaustion forces a crash and automatic restart.

CVSS severity7.1
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in Junos OS Evolved l2ald allows remote attackers on an adjacent network to crash and restart devices. Certain MAC table updates cause l2ald to retain small allocations for L2Rtinfo and NHOpaqueTlv objects instead of releasing them, steadily consuming system memory. No authentication or user interaction is required, but the attacker must share an adjacent network and repeat the triggering updates until memory exhaustion forces a crash and automatic restart.

The record

CVE
CVE-2024-39557
Published
Jul 10, 2024
Updated
Aug 2, 2024
Vendor
Juniper Networks
Product
Junos OS Evolved
Classifications
CWE-400, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 10, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <21.4R3-S8-EVO
  2. Affected versionversion=22.2-EVO <22.2R3-S4-EVO
  3. Affected versionversion=22.3-EVO <22.3R3-S3-EVO
  4. Affected versionversion=22.4-EVO <22.4R3-EVO
  5. Affected versionversion=23.2-EVO <23.2R2-EVO

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OS Evolvedversion=0 <21.4R3-S8-EVO; version=22.2-EVO <22.2R3-S4-EVO; version=22.3-EVO <22.3R3-S3-EVO; version=22.4-EVO <22.4R3-EVO; version=23.2-EVO <23.2R2-EVO

Published CVSS scores

6.5Juniper Networks, Inc.CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.1Juniper Networks, Inc.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/R:A

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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