Security readout for executives and security teams
Plain-English summary
CVE-2023-3640 is a Linux kernel information exposure issue affecting Red Hat Enterprise Linux 8 and 9 kernels. A local, low-privileged user may infer sensitive kernel memory layout details and potentially escalate privileges. This is not a remote attack, but it matters on shared servers, developer systems, and workloads where untrusted local users or compromised accounts exist.
Executive priority
Treat as a high-priority kernel maintenance item, especially for shared Linux infrastructure. It is less urgent than an internet-facing remote exploit, but it can turn a limited local compromise into full system control. Schedule patching through normal emergency or accelerated maintenance windows based on exposure.
Technical view
The flaw involves x86 cpu_entry_area mapping randomization in the Linux kernel. Red Hat describes a remaining leak risk through init_cea_offsets despite prior randomization work related to CVE-2023-0597. The CVSS 3.1 score is 7.0 with local attack vector, high attack complexity, low privileges required, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely on Red Hat Enterprise Linux 8 and 9 systems using affected kernel or kernel-rt packages. The bundle lists RHEL 6 and RHEL 7 as unaffected. Systems with local shell access, shared hosting, containers with host-kernel exposure, or compromised low-privilege accounts deserve priority review.
Exploitation context
No active exploitation is stated in the provided sources, and the CVE is not listed as KEV in the bundle. Exploitation requires local access and is rated high complexity. The business risk is privilege escalation after an attacker already has a foothold or legitimate low-privilege access.
Researcher notes
Key constraints are local access and high complexity. The issue is tied to x86 per-cpu entry area layout exposure when KASLR randomization should reduce predictability. Public sources provided do not include exploit details or independent confirmation of exploitation. Validate against Red Hat advisories rather than assuming upstream or non-Red Hat impact.
Mitigation direction
- Review Red Hat RHSA-2023:6583 and apply applicable kernel updates.
- Prioritize RHEL 8 and RHEL 9 systems with local or shared user access.
- Reduce unnecessary local accounts and shell access on affected systems.
- Follow Red Hat CVE guidance for kernel-rt environments.
Validation and detection
- Inventory RHEL versions and installed kernel or kernel-rt packages.
- Compare installed packages against Red Hat’s CVE page and RHSA-2023:6583.
- Confirm RHEL 6 and 7 systems match Red Hat’s unaffected status.
- After updating, verify systems booted into the 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-385: 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-2023-3640 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 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/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.
SSVC decision data
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:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H15.9redhatVulnerability scoring details
Base CVSS 3.1 score
7HighVector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- Source timelineredhat
Made public.
- Source timelineredhat
Reported to Red Hat.
- 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
- RHSA-2023:6583CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2023-3640CVE reference, redhat · vdb-entry, x_refsource_REDHAT
- RHBZ#2217523CVE reference, redhat · issue-tracking, x_refsource_REDHAT
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.
Covert Timing Channel
Covert Timing Channel represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.