CVE-2023-4155: Sev-es / sev-snp vmgexit double fetch vulnerability

Ubuntu release	Source package	Vendor state	Fixed version	Evidence
Ubuntu 24.04 LTSnoble · standard archive	`linux-raspi-realtime`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 4 Sept 2026

Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available

What, why and how

A flaw was found in KVM AMD Secure Encrypted Virtualization (SEV) in the Linux kernel. A KVM guest using SEV-ES or SEV-SNP with multiple vCPUs can trigger a double fetch race condition vulnerability and invoke the `VMGEXIT` handler recursively. If an attacker manages to call the handler multiple times, they can trigger a stack overflow and cause a denial of service or potentially guest-to-host escape in kernel configurations without stack guard pages (`CONFIG_VMAP_STACK`).

What

Why

The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

How

An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may disrupt the affected service.

What

Why

The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

How

An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may disrupt the affected service.

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: local access → Time-of-check Time-of-use (TOCTOU) Race Condition → disrupt the affected service
Attack surface: Local
Privileges required: High: elevated access is required
User interaction: None
Attack complexity: High: exploitation depends on specific conditions
Security boundary: Changed: exploitation can affect a different security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-367 ↗
CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition. The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:N/A:H
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land: The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.

Denial of serviceCWE-367

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2023-54035Official EUVD mapping

0 linked advisory records.

Official EUVD record

BSI · German · WID-SEC-W-2024-1086IBM QRadar SIEM: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in IBM QRadar SIEM ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, einen Denial-of-Service-Zustand herbeizuführen, vertrauliche Informationen offenzulegen, Dateien zu manipulieren, seine Privilegien zu erweitern, einen Cross-Site-Scripting (XSS)-Angriff durchzuführen oder einen nicht spezifizierten Angriff auszuführen.

Sev-es / sev-snp vmgexit double fetch vulnerability

National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

EUVD-2023-54035

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.