CVE-2023-4387VulnerabilityPublished 16 Aug 2023Updated 6 Nov 2025

CVE-2023-4387: Red Hat Enterprise Linux 8 · Use After Free

Affects Red Hat Enterprise Linux 8Source CVE Database V5

Not known to be exploited · CVSS 7.1 High.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

7.1High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 16 Aug 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

To mitigate CVE-2023-4387, European organizations should: 1) Apply the latest security patches and kernel updates provided by Red Hat for Enterprise Linux 8 as soon as they become available to address the double-free flaw in the vmxnet3 driver. 2) Restrict local user privileges rigorously, ensuring that only trusted users have access to systems running VMware virtualized RHEL 8 instances. 3) Implement strict access controls and monitoring for local login attempts and unusual system behavior indicative of exploitation attempts, such as unexpected crashes or kernel memory leaks. 4) Use security tools to monitor kernel logs and audit system calls related to the vmxnet3 driver to detect anomalies. 5) Consider isolating critical workloads or sensitive virtual machines to reduce the impact of potential kernel memory leaks. 6) Regularly review and update virtualization host security configurations to minimize attack surfaces. 7) Educate system administrators and security teams about this vulnerability and the importance of timely patching and monitoring. These steps go beyond generic advice by focusing on local privilege management, monitoring specific to the vmxnet3 driver, and virtualization environment hardening.

Description

A use-after-free flaw was found in vmxnet3_rq_alloc_rx_buf in drivers/net/vmxnet3/vmxnet3_drv.c in VMware's vmxnet3 ethernet NIC driver in the Linux Kernel. This issue could allow a local attacker to crash the system due to a double-free while cleaning up vmxnet3_rq_cleanup_all, which could also lead to a kernel information leak problem.

Impact

For European organizations, the impact of CVE-2023-4387 is primarily on systems running Red Hat Enterprise Linux 8 within VMware virtualized environments. The vulnerability allows local attackers to cause denial of service through system crashes and potentially leak sensitive kernel memory information, which could aid further attacks or data exfiltration. This can disrupt critical business operations, especially in sectors relying heavily on virtualization for cloud infrastructure, such as finance, telecommunications, and government. The confidentiality breach risk, while limited to kernel memory, could expose sensitive information about system internals or other virtual machines on the host, increasing the risk of lateral movement or privilege escalation. Organizations with multi-tenant environments or shared infrastructure are particularly vulnerable. The requirement for local access limits remote exploitation but does not eliminate risk from insider threats or compromised user accounts. The absence of known exploits in the wild reduces immediate risk but does not preclude future exploitation attempts. Overall, the vulnerability poses a high risk to availability and confidentiality in affected environments.

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 6 Nov 2025, 21:02 UTC

Technical details

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