Security readout for executives and security teams
Plain-English summary
CVE-2021-29707 is a local privilege escalation flaw in IBM Power HMC. A user with local access to the restricted shell could gain root access. Because HMC manages IBM Power infrastructure, compromise could affect administrative control, availability, and confidentiality of managed systems.
Executive priority
Prioritize remediation for any affected HMC because root access on a management console can threaten critical IBM Power operations. Urgency is high where many administrators share HMC access or where local console access is weakly controlled.
Technical view
IBM reports that HMC versions 9.1.910.0 and 9.2.950.0 allow local escalation to root from a restricted shell. The CVSS 3.0 score is 8.4, with high confidentiality, integrity, and availability impact. The source bundle does not name a CWE or provide root-cause detail.
Likely exposure
Exposure is limited to environments running IBM Power HMC 9.1.910.0 or 9.2.950.0 where users can obtain local restricted-shell access. Internet exposure alone is not indicated by the sources.
Exploitation context
The CVE is not listed in CISA KEV in the provided bundle, and the sources mark exploit maturity as unproven. Treat exploitation as plausible after local access, but do not assume active exploitation from the available evidence.
Researcher notes
Evidence is concise: vendor and CVE records identify affected versions, local privilege escalation, root outcome, and CVSS 8.4. The bundle does not provide technical root cause, exploit details, patch version names, or confirmed exploitation. Avoid inferring affected releases beyond the two listed versions.
Mitigation direction
- Identify any IBM Power HMC instances running 9.1.910.0 or 9.2.950.0.
- Review IBM advisory 6473347 and apply IBM's published remediation guidance.
- Restrict local and restricted-shell access to trusted administrators only.
- Audit HMC users, roles, and authentication paths pending remediation.
- Monitor HMC logs for unusual privilege changes or administrative activity.
Validation and detection
- Inventory HMC version numbers and match them against the affected versions.
- Confirm remediation status against IBM support advisory 6473347.
- Review which users can access the HMC restricted shell locally.
- Check recent HMC logs for unexpected root-level or administrative actions.
- Document compensating controls if remediation cannot be applied immediately.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-29707 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.4 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AC:L/C:H/A:H/AV:L/S:U/I:H/PR:N/UI:N/RL:O/RC:C/E:U
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AC:L/C:H/A:H/AV:L/S:U/I:H/PR:N/UI:N/RL:O/RC:C/E:U2.55.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
8.4HighVector: CVSS:3.0/AC:L/C:H/A:H/AV:L/S:U/I:H/PR:N/UI:N/RL:O/RC:C/E:U
Source materials
- CVE List V5 sourceCVE List V5
- https://www.ibm.com/support/pages/node/6473347CVE reference · x_refsource_CONFIRM
- ibm-hmc-cve202129707-priv-escalation (200879)CVE reference · vdb-entry, x_refsource_XF
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.