CVE-2023-34324VulnerabilityPublished 5 Jan 2024Updated 5 Jun 2025

CVE-2023-34324: Linux · Vulnerability

Affects LinuxSource CVE Database V5

Not known to be exploited · CVSS 4.9 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

4.9Medium

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

EPSS: 1.1% chance of exploitation in 30 days – higher than 66% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
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: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
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 5 Jan 2024
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-2023-34324, European organizations should prioritize the following actions: 1) Apply Linux kernel updates as soon as patches become available from trusted vendors or distributions, ensuring Xen-related fixes are included. 2) Monitor Xen hypervisor and guest kernel versions to identify vulnerable deployments. 3) Limit the use of paravirtual devices and event channel closures during critical operations to reduce the chance of triggering the deadlock. 4) Implement strict access controls and monitoring to prevent unauthorized privilege escalation within guest VMs, as exploitation requires high privileges. 5) Consider architectural changes to reduce reliance on Xen paravirtualization where feasible, or migrate to alternative virtualization technologies less susceptible to this issue. 6) Employ robust incident response plans to detect and recover from potential DoS conditions caused by this vulnerability. 7) Engage with Linux and Xen communities to stay informed about patches and recommended configurations. 8) Test updates and configuration changes in staging environments to ensure stability before production deployment.

Description

Closing of an event channel in the Linux kernel can result in a deadlock. This happens when the close is being performed in parallel to an unrelated Xen console action and the handling of a Xen console interrupt in an unprivileged guest. The closing of an event channel is e.g.triggered by removal of a paravirtual device on the other side. As this action will cause console messages to be issued on the other side quite often, the chance of triggering the deadlock is not neglectable. Note that 32-bit Arm-guests are not affected, as the 32-bit Linux kernel on Arm doesn't use queued-RW-locks, which are required to trigger the issue (on Arm32 a waiting writer doesn't block further readers to get the lock).

Impact

For European organizations, especially those utilizing Xen virtualization with Linux guests, this vulnerability poses a risk of denial of service through deadlocks in the kernel. Organizations running cloud infrastructure, virtualized servers, or private clouds using Xen hypervisors could experience service interruptions or degraded performance. This is particularly relevant for data centers, hosting providers, and enterprises relying on Linux-based virtual machines for critical applications. The deadlock could disrupt business continuity, affect service level agreements (SLAs), and increase operational costs due to downtime or recovery efforts. Since the vulnerability requires high privileges within the guest, it is more likely to be exploited by insiders or attackers who have already compromised a guest VM. However, the network attack vector means that remote exploitation is possible if such privileges can be obtained remotely. The absence of confidentiality or integrity impact limits data breach risks, but availability impacts could indirectly affect compliance with regulations like GDPR if services become unavailable. Additionally, sectors with high dependency on virtualization, such as finance, telecommunications, and government, could face operational risks.

Summary

CVE-2023-34324 is a medium-severity vulnerability in the Linux kernel related to the handling of event channels in Xen paravirtualized environments. Specifically, the vulnerability arises when an event channel is closed concurrently with unrelated Xen console actions and the processing of Xen console interrupts within an unprivileged guest. The root cause is a deadlock condition triggered by the use of queued read-write locks (queued-RW-locks) in the Linux kernel on certain architectures. When an event channel closure occurs—often due to the removal of a paravirtual device on the host side—console messages are frequently generated on the guest side, increasing the likelihood of the deadlock. This deadlock effectively halts progress in the affected kernel threads, causing a denial of service (DoS) condition by freezing the guest system or degrading its responsiveness. Notably, 32-bit ARM guests are not affected because their Linux kernel implementations do not use queued-RW-locks, which are essential for this deadlock to manifest. The vulnerability does not impact confidentiality or integrity but affects availability, as it can cause system hangs. The CVSS 3.1 score is 4.9 (medium), reflecting network attack vector, low attack complexity, required privileges (high), no user interaction, unchanged scope, no impact on confidentiality or integrity, but high impact on availability. No known exploits are reported in the wild, and no patches are linked in the provided data, indicating that mitigation may require kernel updates or configuration changes in Xen environments.

CWE-400Uncontrolled Resource Consumption (opens in a new tab)
Class weaknessLikelihood of exploit: High
The product does not properly control the allocation and maintenance of a limited resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place.
Architecture and Design
Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or; uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Architecture and Design
Ensure that protocols have specific limits of scale placed on them.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Regular Expression Exponential Blowup (opens in a new tab)
Sustained Client Engagement (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 7 Jul 2025, 18:57 UTC

WeaknessesCWE-400

Technical details

References

Community reviews

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