CVE-2026-64055 net: ethernet: cortina: Carry over frag counter

What is CVE-2026-64055?

CVE-2026-64055 is a critical vulnerability in Linux kernel, published on 19 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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.

Which versions are affected by CVE-2026-64055?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64055?

Apply the vendor's patch.

Is CVE-2026-64055 being exploited?

There is no known exploitation of CVE-2026-64055 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-64055, DEBIAN-CVE-2026-64055, GHSA-j6pg-f87q-4363, UBUNTU-CVE-2026-64055.