CVE-2021-39296Public exploitNetwork attack vector

Root access via pre-auth session privilege escalation

Published Sep 9, 2021 · Updated Aug 4, 2024

Authentication bypass in OpenBMC 2.9 netipmid allows remote attackers to gain root access through crafted IPMI LAN+ messages. Netipmid creates and enables a session before authentication succeeds, then honors a privilege request that raises USER access to ADMIN. Network access to the IPMI service and an existing username are sufficient to change the root password and obtain full BMC control.

CVSS severity10.0
Critical
EPSS probability3.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in OpenBMC 2.9 netipmid allows remote attackers to gain root access through crafted IPMI LAN+ messages. Netipmid creates and enables a session before authentication succeeds, then honors a privilege request that raises USER access to ADMIN. Network access to the IPMI service and an existing username are sufficient to change the root password and obtain full BMC control.

The record

CVE
CVE-2021-39296
Published
Sep 9, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 9, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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

10.0NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
10.0IntelCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1190Exploit Public-Facing Application

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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