Security readout for executives and security teams
Plain-English summary
This flaw affects Lanner IAC-AST2500A BMC firmware 1.10.0. An attacker who already has high-privilege authentication could exploit spx_restservice to run code as root. Business risk is highest where BMC management is reachable beyond tightly controlled admin networks.
Executive priority
Treat as priority remediation for any confirmed affected BMCs. The flaw needs privileged access, but compromise could give root-level control of infrastructure management hardware, which can affect availability and incident recovery.
Technical view
CVE-2021-26731 is command injection plus multiple stack-based buffer overflows in modifyUserb_func within spx_restservice. The CVSS 3.1 score is 9.1: network reachable, low complexity, high privileges required, no user interaction, changed scope, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited by the supplied affected list: Lanner Inc IAC-AST2500A standard firmware version 1.10.0. The CVE bundle marks other versions/products as unaffected by default, so asset and firmware confirmation are essential.
Exploitation context
The source bundle does not show CISA KEV listing or other evidence of active exploitation. Exploitation requires authenticated high privileges, but successful exploitation can run arbitrary code with root privileges on the BMC service.
Researcher notes
Focus validation on firmware 1.10.0 and the BMC spx_restservice user-management path. Do not broaden scope beyond IAC-AST2500A without evidence. The public source bundle names impact and affected version but does not include patch details.
Mitigation direction
- Identify any Lanner IAC-AST2500A devices running standard firmware 1.10.0.
- Check Lanner and Nozomi guidance for fixed firmware or vendor-approved mitigations.
- Restrict BMC management access to trusted administrative networks only.
- Review and reduce high-privilege BMC accounts where operationally possible.
- Monitor BMC management activity for unexpected authenticated changes.
Validation and detection
- Inventory Lanner IAC-AST2500A assets and record exact firmware versions.
- Confirm whether spx_restservice is exposed on reachable management networks.
- Verify only authorized administrators can authenticate to affected BMC interfaces.
- Review vendor advisories before declaring remediation complete.
- Check logs for unusual high-privilege activity around BMC user management.
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
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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.
CWE-121: Exact CWE lookup
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Open ATT&CK lookupCWE-94: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-26731 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
- Critical
- CVSS
- 9.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
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:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H2.36Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.1CriticalVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Source materials
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.