CVE-2023-28984

PFE restart via l2alm use-after-free race

Published Apr 17, 2023 · Updated Feb 5, 2025

Use-after-free in Junos OS l2alm on QFX Series allows adjacent attackers to crash and restart the Packet Forwarding Engine. During heavy MAC learning and aging, improperly synchronized concurrent access lets l2alm use freed memory in a race outside attacker control. The attacker must be adjacent and generate sustained MAC-table churn; successful triggering interrupts forwarding until the PFE restarts.

CVSS severity5.3
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Junos OS l2alm on QFX Series allows adjacent attackers to crash and restart the Packet Forwarding Engine. During heavy MAC learning and aging, improperly synchronized concurrent access lets l2alm use freed memory in a race outside attacker control. The attacker must be adjacent and generate sustained MAC-table churn; successful triggering interrupts forwarding until the PFE restarts.

The record

CVE
CVE-2023-28984
Published
Apr 17, 2023
Updated
Feb 5, 2025
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-362, CWE-416, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 5, 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=20.2 <20.2R3-S7
  2. Affected versionversion=20.3 <20.3R3-S6
  3. Affected versionversion=20.4 <20.4R3-S5
  4. Affected versionversion=21.1 <21.1R3-S4
  5. Affected versionversion=21.2 <21.2R3-S3
  6. Affected versionversion=21.3 <21.3R3-S3
  7. Affected versionversion=21.4 <21.4R3
  8. Affected versionversion=22.1 <22.1R3
  9. Affected versionversion=22.2 <22.2R2
  10. Affected versionversion=unspecified <19.4R3-S10

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=20.2 <20.2R3-S7; version=20.3 <20.3R3-S6; version=20.4 <20.4R3-S5; version=21.1 <21.1R3-S4; version=21.2 <21.2R3-S3; version=21.3 <21.3R3-S3; version=21.4 <21.4R3; version=22.1 <22.1R3; version=22.2 <22.2R2; version=unspecified <19.4R3-S10

Published CVSS scores

5.3Juniper NetworksCVSS:3.1/AV:A/AC:H/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.

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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-416Use After Free
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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