CVE-2024-21587

Service interruption via bbe-smgd session memory leak

Published Jan 12, 2024 · Updated Jun 3, 2025

Improper exception handling in Juniper Networks Junos OS on MX Series allows attackers to exhaust memory by flapping DHCP sessions. The bbe-smgd daemon fails to release a small amount of memory whenever a DHCP subscriber logs in, so repeated session churn accumulates until memory starvation. Exposure requires BFD liveness detection for DHCP subscribers and direct network attachment; sustained churn interrupts service.

CVSS severity6.5
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper exception handling in Juniper Networks Junos OS on MX Series allows attackers to exhaust memory by flapping DHCP sessions. The bbe-smgd daemon fails to release a small amount of memory whenever a DHCP subscriber logs in, so repeated session churn accumulates until memory starvation. Exposure requires BFD liveness detection for DHCP subscribers and direct network attachment; sustained churn interrupts service.

The record

CVE
CVE-2024-21587
Published
Jan 12, 2024
Updated
Jun 3, 2025
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-755, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 12, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 2025Record 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 <20.4R3-S9
  2. Affected versionversion=21.2 <21.2R3-S7
  3. Affected versionversion=21.3 <21.3R3-S5
  4. Affected versionversion=21.4 <21.4R3-S5
  5. Affected versionversion=22.1 <22.1R3-S4
  6. Affected versionversion=22.2 <22.2R3-S3
  7. Affected versionversion=22.3 <22.3R3-S2
  8. Affected versionversion=22.4 <22.4R2-S2, 22.4R3
  9. Affected versionversion=23.2 <23.2R1-S1, 23.2R2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=0 <20.4R3-S9; version=21.2 <21.2R3-S7; version=21.3 <21.3R3-S5; version=21.4 <21.4R3-S5; version=22.1 <22.1R3-S4; version=22.2 <22.2R3-S3; version=22.3 <22.3R3-S2; version=22.4 <22.4R2-S2, 22.4R3; version=23.2 <23.2R1-S1, 23.2R2

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

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.

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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-755Improper Handling of Exceptional Conditions
T1499.004Application or System Exploitation

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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