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Security Bulletin: This Power System update is being released to address CVE-2021-3505

Security Bulletin


A flaw was found in libtpms in versions before 0.8.0. The TPM 2 implementation returns 2048 bit keys with ~1984 bit strength due to a bug in the TCG specification. The bug is in the key creation algorithm in RsaAdjustPrimeCandidate(), which is called before the prime number check.

Vulnerability Details

CVEID:   CVE-2021-3505
DESCRIPTION:   libtpms could allow a local attacker to obtain sensitive information, caused by an issue with the TPM 2 implementation returns 2048 bit keys with ~1984 bit strength. By utilize cryptographic attack techniques, an attacker could exploit this vulnerability to obtain sensitive information, and use this information to launch further attacks against the affected system.
CVSS Base score: 6.2
CVSS Temporal Score: See: for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)

Affected Products and Versions

Affected Product(s)Version(s)
PowerVM HypervisorFW1050 (all versions using vTPM 2.0 with encryption level Power10v1)
PowerVM HypervisorFW1030 (all versions using vTPM 2.0)
PowerVM HypervisorFW1020 (all versions using vTPM 2.0)


IBM recommends customers with the products below install FW1050.00 or newer and perform the mitigation steps below to remediate this vulnerability.

Power 10

1) IBM Power System E1080 (9080-HEX)

2) IBM Power System S1022 (9105-22A)

3) IBM Power System S1024 (9105-42A)

4) IBM Power System S1022s (9105-22B)

5) IBM Power System S1014 (9105-41B)

6) IBM Power System L1022 (9786-22H)

7) IBM Power System L1024 (9786-42H)

8) IBM Power System E1050 (9043-MRX)


To fully mitigate your system you must update all partitions that are using vTPM2.0 to the 'Power10v2' encryption level or higher.  Please follow the detailed steps outlined here to accomplish that:

Workarounds and Mitigations


Get Notified about Future Security Bulletins




Change History

29 Feb 2024: Initial Publication

*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.


According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.

Document Location


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Document Information

Modified date:
29 February 2024