CVE-2021-29891Network attack vector

Network-service outage via weak identity certificate

Published Aug 22, 2022 · Updated Sep 16, 2024

Denial of service in the IBM Power System AC922 BMC on OP910 and OP940 allows remote authenticated users to interrupt network services. The BMC HTTPS server accepts a site identity certificate whose RSA or ECC key falls below IBM's supported strength threshold, preventing network-service operation. Administrative certificate-upload access is required; the documented consequence is service loss without reported disclosure or data modification.

CVSS severity4.9
Medium
EPSS probability0.45%
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 the IBM Power System AC922 BMC on OP910 and OP940 allows remote authenticated users to interrupt network services. The BMC HTTPS server accepts a site identity certificate whose RSA or ECC key falls below IBM's supported strength threshold, preventing network-service operation. Administrative certificate-upload access is required; the documented consequence is service loss without reported disclosure or data modification.

The record

CVE
CVE-2021-29891
Published
Aug 22, 2022
Updated
Sep 16, 2024
Vendor
IBM
Product
IBM Power System AC922
Classifications
CWE-434, T1489
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Aug 22, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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?

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

  1. Affected versionversion=OP910
  2. Affected versionversion=OP940

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

IBM · IBM Power System AC922version=OP910; version=OP940

Published CVSS scores

4.9NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
4.9IBMCVSS:3.0/AV:N/AC:L/PR:H/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)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1489Service Stop

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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