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CVE-2026-64055

Vulnerability intelligence

Published Jul 19, 2026Sources checked Oct 27, 2026
9.8CRITICALCVSS out of 10
What this means

Review the available evidence

CVE-2026-64055 and is rated Critical severity with a CVSS score of 9.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Ubuntu Security Notices guidance

Vendor revision: Sep 29, 2026
Vendor remediation details

This update corrects flaws in the following subsystems: - ARM32 architecture; - ARM64 architecture; - PowerPC architecture; - Compute Acceleration Framework; - Drivers core; - Bluetooth drivers; - Arm Firmware Framework for ARMv8-A(FFA); - EFI core; - GPU drivers; - Hardware monitoring drivers; - InfiniBand drivers; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - SCSI subsystem; - SPI subsystem; - Network file systems library; - NTFS3 file system; - SMB network file system; - File systems infrastructure; - Software nodes and device properties; - Bluetooth subsystem; - Netfilter; - Tracing infrastructure; - io_uring subsystem; - IRQ subsystem; - KProbes tracing; - Memory management; - B.A.T.M.A.N.

Ubuntu Security Notices guidance

Vendor revision: Sep 25, 2026
Vendor remediation details

This update corrects flaws in the following subsystems: - ARM32 architecture; - ARM64 architecture; - PowerPC architecture; - Compute Acceleration Framework; - Drivers core; - Bluetooth drivers; - Arm Firmware Framework for ARMv8-A(FFA); - EFI core; - GPU drivers; - Hardware monitoring drivers; - InfiniBand drivers; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - SCSI subsystem; - SPI subsystem; - Network file systems library; - NTFS3 file system; - SMB network file system; - File systems infrastructure; - Software nodes and device properties; - Bluetooth subsystem; - Netfilter; - Tracing infrastructure; - io_uring subsystem; - IRQ subsystem; - KProbes tracing; - Memory management; - B.A.T.M.A.N.

Ubuntu Security Notices guidance

Vendor revision: Sep 22, 2026
Vendor remediation details

This update corrects flaws in the following subsystems: - ARM32 architecture; - ARM64 architecture; - PowerPC architecture; - Compute Acceleration Framework; - Drivers core; - Bluetooth drivers; - Arm Firmware Framework for ARMv8-A(FFA); - EFI core; - GPU drivers; - Hardware monitoring drivers; - InfiniBand drivers; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - SCSI subsystem; - SPI subsystem; - Network file systems library; - NTFS3 file system; - SMB network file system; - File systems infrastructure; - Software nodes and device properties; - Bluetooth subsystem; - Netfilter; - Tracing infrastructure; - io_uring subsystem; - IRQ subsystem; - KProbes tracing; - Memory management; - B.A.T.M.A.N.

CISA KEVNot listedBased on the latest collected catalog
EPSS0.5%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview

What is CVE-2026-64055?

In the Linux kernel, the following vulnerability has been resolved:

net: ethernet: cortina: Carry over frag counter

The gmac_rx() NAPI poll function assembles packets in an SKB from a ring buffer.

If the ring buffer gets completely emptied during a poll cycle, we exit gmac_rx(), but the packet is not yet completely assembled in the SKB, yet the fragment counter frag_nr is reset to zero on the next invocation.

Solve this by making the RX fragment counter a part of the port struct, and carry it over between invocations.

Reset the fragment counter only right after calling napi_gro_frags(), on error (after calling napi_free_frags()) or if stopping the port.

Reset it in some place where not strictly necessary just to emphasize what is going on.

This was found by Sashiko during normal patch review.

Source: NVD