VulnerabilityPublished 11 Dec 2023Updated 21 Nov 2025

CVE-2023-6679: Red Hat Enterprise Linux 9 · NULL Pointer Dereference

Affects Red Hat Enterprise Linux 9Source CVE Database V5

Not known to be exploited · CVSS 5.5 Medium.

Data as of 26 Oct 2026, 09:15 UTC

CVSS 3.1 base score

5.5Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 23% 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:N/I:N/A:H

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
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: None: There is no loss of confidentiality within the impacted component.
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 11 Dec 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 26 Oct 2026.

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

Organizations should apply security patches from Red Hat as soon as they become available to address CVE-2023-6679. Until patches are deployed, restrict local access to trusted personnel only and implement strict access controls and monitoring on systems running Red Hat Enterprise Linux 9. Employ kernel hardening techniques such as enabling kernel lockdown features and using security modules like SELinux to limit the ability of low-privilege users to interact with kernel subsystems. Regularly audit user accounts and remove unnecessary local accounts to reduce the attack surface. Implement comprehensive logging and alerting to detect unusual system crashes or kernel panics that may indicate exploitation attempts. In virtualized or containerized environments, isolate critical workloads to minimize the impact of potential DoS conditions. Additionally, maintain up-to-date backups and disaster recovery plans to quickly restore services in case of disruption. Coordinate with Red Hat support and subscribe to security advisories to receive timely updates on patches and mitigation guidance.

Description

CVE-2023-6679 is a medium severity vulnerability in Red Hat Enterprise Linux 9 involving a null pointer dereference in the Digital Phase Locked Loop (DPLL) subsystem of the Linux kernel. Specifically, the flaw exists in the dpll_pin_parent_pin_set() function within the dpll_netlink.c driver code. Exploiting this vulnerability can cause a denial of service (DoS) by crashing the kernel, impacting system availability. The vulnerability requires local access with low privileges and no user interaction, making exploitation somewhat limited but still feasible in certain scenarios. No known exploits are currently reported in the wild. European organizations running Red Hat Enterprise Linux 9 on critical infrastructure or servers could face service disruptions if targeted. Mitigation involves applying vendor patches once available and restricting local access to trusted users. Countries with significant Red Hat Enterprise Linux adoption and critical infrastructure reliance, such as Germany, France, and the UK, are most likely to be affected. The CVSS score of 5.

Impact

For European organizations, the primary impact of CVE-2023-6679 is a potential denial of service on systems running Red Hat Enterprise Linux 9. This can lead to unplanned downtime of critical servers, affecting business continuity, especially in sectors relying on high availability such as finance, telecommunications, manufacturing, and public services. Since the vulnerability requires local access, the risk is higher in environments where multiple users have shell access or where attackers can gain foothold through other means. The disruption of the DPLL subsystem could also impact time synchronization services, which are critical for logging, security monitoring, and compliance. Although confidentiality and integrity are not directly affected, availability issues can cascade into operational disruptions and potential regulatory non-compliance. European organizations with strict uptime requirements and those operating critical infrastructure should prioritize mitigation. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially from insider threats or attackers who gain local access through other vulnerabilities.

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Description

AI analysisMachine-generated, updated 28 Nov 2025, 06:55 UTC

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