VulnerabilityPublished 19 Jul 2025Updated 18 Nov 2025

CVE-2025-38351: Linux kernel · KVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush

Source GCVE Database

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Not known to be exploited · CVSS 5.5 Medium.

Data as of 13 Nov 2026, 20:01 UTC

CVSS 3.1 base score

5.5Medium

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

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 19 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 13 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity 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.

ghsa-x77v-68j6-p42v

What to do

AI-suggested

A fix is available in the Linux kernel that skips non-canonical GVAs during PV TLB flush hypercall processing, preventing INVVPID failures on Intel CPUs. Users should update to a kernel version that includes this fix. No additional action is required if the kernel is already patched. There is no indication of active exploitation in the wild.

Description

CVE-2025-38351 is a vulnerability in the Linux kernel's KVM subsystem related to Hyper-V hypercalls. It involves improper handling of non-canonical guest virtual addresses (GVAs) during paravirtualized TLB flush operations. Non-canonical GVAs passed to Intel's INVVPID instruction cause a VM failure and kernel warnings, while AMD silently ignores them. The fix involves skipping non-canonical GVAs to prevent these failures.

Impact

The impact is limited to causing VM failures and kernel warnings on Intel CPUs when non-canonical GVAs are passed during PV TLB flush hypercalls. There is no confidentiality, integrity, or data disclosure impact. The vulnerability could cause denial of service by triggering VM failures. AMD CPUs are unaffected due to their INVLPGA instruction ignoring non-canonical addresses silently.

Summary

This vulnerability affects KVM guests with Hyper-V hypercalls enabled in the Linux kernel. The hypercalls HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST and HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX allow a guest to request invalidation of virtual TLB entries by passing a list of GVAs. However, non-canonical GVAs were not filtered out and were passed to the INVVPID instruction on Intel CPUs, causing VM failures and kernel warnings. AMD CPUs ignore such addresses without error. The vulnerability arises because the Linux KVM implementation did not skip non-canonical GVAs during PV TLB flush processing. The resolution is to skip these non-canonical addresses to avoid triggering INVVPID failures, aligning behavior with Hyper-V specifications and real Hyper-V implementations.

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