Security Resilience

CVE-2023-3640

Redhat Enterprise Linux 8.0 … 9.0

Published
24 July 2023
Modified
21 July 2026
CVSS Score v3.1 7.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0076 54th percentile
Risk Priority 53 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-3640 is a high-severity Covert Timing Channel (CWE-385) vulnerability in Redhat Enterprise Linux. Its CVSS base score is 7.0 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data Obfuscation (T1001); ranked in the top 46% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

A possible unauthorized memory access flaw was found in the Linux kernel's cpu_entry_area mapping of X86 CPU data to memory, where a user may guess the location of exception stacks or other important data. Based on the previous CVE-2023-0597, the…

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'Randomize per-cpu entry area' feature was implemented in /arch/x86/mm/cpu_entry_area.c, which works through the init_cea_offsets() function when KASLR is enabled. However, despite this feature, there is still a risk of per-cpu entry area leaks. This issue could allow a local user to gain access to some important data with memory in an expected location and potentially escalate their privileges on the system.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001 Data Obfuscation Command And Control
Adversaries may obfuscate command and control traffic to make it more difficult to detect.
T1001.002 Steganography Command And Control
Adversaries may use steganographic techniques to hide command and control traffic to make detection efforts more difficult.
T1001.003 Protocol or Service Impersonation Command And Control
Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.
T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-6240Same product: Linux Linux Kernel
CVE-2024-0564Same product: Linux Linux Kernel
CVE-2024-0775Same product: Linux Linux Kernel
CVE-2023-6610Same product: Linux Linux Kernel
CVE-2023-4459Same product: Linux Linux Kernel
CVE-2023-6176Same product: Linux Linux Kernel
CVE-2023-1095Same product: Linux Linux Kernel
CVE-2024-0646Same product: Linux Linux Kernel
CVE-2023-1192Same product: Linux Linux Kernel
CVE-2023-2513Same product: Linux Linux Kernel

Affected Assets

linux
linux kernel
all versions
redhat
enterprise linux
8.0, 9.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

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Detect
Catch it (NIST detect / respond)

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Harden
Shrink the surface (DISA STIG)
  • 1 hardening rule · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)

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Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-385 CWE-203

Directly targets covert timing channels by requiring identification and bandwidth estimation, enabling mitigation that reduces or eliminates their usability.

addresses: CWE-203

Misdirection can normalize or falsify responses to eliminate observable discrepancies that aid reconnaissance.

addresses: CWE-203

Prevents attackers from using observable differences in error responses to infer internal system details or state.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

DE.CM-09 partial match
blocks

Runtime monitoring of hardware/software behavior can detect anomalous timing patterns that indicate covert channels.

ID.RA-01 partial match
blocks

Vulnerability identification processes can surface timing-channel weaknesses during design or code analysis.

PR.PS-06 partial match
blocks

Secure development practices (reviews, testing) directly reduce introduction of timing-channel vulnerabilities in code.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

removes
removes
removes
removes

References