Security readout for executives and security teams
Plain-English summary
A missing end marker in a Linux kernel table can make AMD CPU detection read beyond the table. The supplied CVSS 7.1 assessment indicates possible disclosure of kernel data or system failure. The evidence does not establish a practical trigger or widespread exploitability.
Executive priority
Treat as a high-priority kernel maintenance issue, especially on AMD Linux systems permitting local users. Schedule expedited remediation through supported distribution updates, but avoid emergency incident declarations absent evidence of exploitation or confirmed exposure.
Technical view
The erratum_1386_microcode array lacks the empty sentinel expected by x86_match_cpu_with_stepping(), causing an out-of-bounds read (CWE-125). The published vector is local, low-complexity, low-privilege, without user interaction, with high confidentiality and availability impact. Upstream fixes append the required empty entry.
Likely exposure
Prioritize x86 Linux systems using AMD processors and kernel builds identified as affected in the CVE record. The supplied version data names 6.10, 6.11.11, 6.12.2, and 6.13 but lacks clear range operators, so confirm distribution-specific backports and status with the vendor.
Exploitation context
CISA KEV status is false, and the supplied sources do not report active exploitation or a public proof of concept. Although the CVSS vector models local low-privilege access, the bundle does not document the precise trigger, reliability, or real-world exploitation conditions.
Researcher notes
The core defect is sentinel omission leading to an array over-read during AMD CPU matching. The source bundle supports confidentiality and availability impact through CVSS, but provides no crash trace, leaked-data path, trigger analysis, or exploit evidence. Version boundaries are insufficiently expressed and require vendor confirmation.
Mitigation direction
- Apply a vendor-supported kernel containing the upstream array-termination fix.
- Review distribution advisories for affected versions and backported patches.
- Prioritize AMD-based multi-user systems where local access is available.
- Reboot into the remediated kernel according to normal change procedures.
Validation and detection
- Inventory running kernel versions and CPU architecture across Linux systems.
- Confirm affected AMD systems against distribution-specific security advisories.
- Verify the installed kernel contains an equivalent fix or referenced upstream commit.
- After remediation, confirm systems are running the intended updated kernel.
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.
CWE-125: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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 lookupCVE-2024-56721 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
- 7.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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.
SSVC decision data
CVSS vector scores
2 official scoresWe 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:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H1.85.2LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H1.85.2CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
7.1HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Base CVSS 3.1 score
7.1HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/82d6b82cf89d950982ac240ba068c3a7e1f23b0aCVE reference, Linux
- https://git.kernel.org/stable/c/ccfee14f08b8699132b87bc6d78e0fa75bf094ddCVE reference, Linux
- https://git.kernel.org/stable/c/ff6cdc407f4179748f4673c39b0921503199a0adCVE reference, Linux
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.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.