External risk intelligence

Linux Kernel igbvf Driver DMA Buffer Leak Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-74495

This vulnerability is located within the Linux kernel network driver (igbvf) handling DMA mapping for TX buffers. It is a low-level memory management issue occurring deep within the kernel's hardware interaction layer, not an internet-facing service or application interface.

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A flaw has been identified in a Linux kernel network driver that could lead to memory leaks under specific error conditions, potentially impacting system stability. This issue was introduced in a previous fix and has been resolved in the latest updates.

Kernel driver has a memory leak.
Confirms relevance and potential exposure.
Address potential system instability.

Attack Path

How an attacker could exploit the issue

An attacker could exploit a flaw in the Linux kernel's `igbvf` network driver to cause a resource leak. This leak occurs when errors happen during the mapping of transmit (TX) buffers, and the driver fails to properly unmap already mapped buffers. Successful exploitation could lead to significant denial of service.

No authentication or privileges needed.
Error during TX buffer DMA mapping.
Resource leak leading to denial of service.

Live Threat

Current exploitation, exposure, and threat context

When an error occurs during TX buffer mapping in the Linux kernel's `igbvf` driver, a DMA mapping could be leaked. This issue is related to how the driver cleans up after encountering an error while processing transmit (TX) buffers, potentially leaving a mapping uncleaned under specific error conditions.

Kernel memory resources.
Unmapped DMA buffers on error.
Potential for denial-of-service.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in the Linux kernel's `igbvf` driver, related to TX DMA error cleanup, primarily impacts infrastructure and platform teams responsible for kernel maintenance and network device drivers. The initial practical step involves identifying all systems running the affected kernel versions, confirming their exposure and business criticality, and then assigning ownership for remediation planning, which may involve vendor coordination for kernel updates.

Infrastructure and platform teams own this.
Verify affected kernel instances and exposure.
Plan kernel updates during maintenance windows.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

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Frequently asked questions

What is the igbvf driver mentioned in CVE-2026-74495?

The igbvf driver is a specific component of the Linux kernel used to manage Intel Gigabit Virtual Function network interfaces. These drivers allow virtual machines or guest operating systems to communicate efficiently with physical network hardware by offloading tasks like direct memory access (DMA) buffer management, which handles the movement of data between memory and network hardware.

How does this Linux kernel vulnerability work?

This is a memory management flaw, specifically a resource leak. When the driver encounters a transmission error, it is supposed to clean up previously prepared memory buffers. Because of an off-by-one calculation error in the cleanup logic, the system fails to unmap one of these buffers, causing that memory to remain held indefinitely rather than being released back to the system.

When does this DMA buffer leak occur?

The leak is triggered specifically during an error condition while mapping transmit (TX) buffers. It does not occur during standard, successful data transmissions. If no error is encountered by the driver during the memory mapping process, the flawed cleanup code path is never activated, and the memory leak will not happen.

Do I need to worry about this if my server is internal?

According to Halo Surface Signal, this vulnerability is very unlikely to be exploited because it is buried deep within the kernel's hardware interaction layer. It is not an internet-facing service or application interface. While it exists within the kernel, the low-level nature of the driver's operation makes it a difficult target for remote attackers regardless of network placement.

What is the recommended first step to respond to this CVE?

Your first step is to perform an inventory of your systems to identify which machines are running the affected kernel versions. Once you have identified these instances, determine their business criticality. You can then schedule the necessary kernel updates provided by your distribution vendor during your next regular maintenance window to resolve the driver flaw.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.