CVE-2021-39295Public exploitNetwork attack vector

BMC management outage via zero-length IPMI payload

Published Apr 15, 2023 · Updated Feb 6, 2025

Denial of service in OpenBMC 2.9 allows remote attackers to disable the BMC's netipmid service with crafted IPMI LAN+ datagrams. The IPMI message parser passes a zero payload length to a range assignment whose computed end pointer precedes its start, crashing netipmid. No authentication is required; repeated UDP packets cause systemd to stop restarting netipmid, leaving remote IPMI management unavailable.

CVSS severity7.5
High
EPSS probability1.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in OpenBMC 2.9 allows remote attackers to disable the BMC's netipmid service with crafted IPMI LAN+ datagrams. The IPMI message parser passes a zero payload length to a range assignment whose computed end pointer precedes its start, crashing netipmid. No authentication is required; repeated UDP packets cause systemd to stop restarting netipmid, leaving remote IPMI management unavailable.

The record

CVE
CVE-2021-39295
Published
Apr 15, 2023
Updated
Feb 6, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 15, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 6, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.1IntelCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L
7.5NIST NVDCVSS:3.1/AV:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

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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