CVE-2026-43194

Technical Description

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

net: consume xmit errors of GSO frames

udpgro_frglist.sh and udpgro_bench.sh are the flakiest tests

currently in NIPA. They fail in the same exact way, TCP GRO

test stalls occasionally and the test gets killed after 10min.

These tests use veth to simulate GRO. They attach a trivial

("return XDP_PASS;") XDP program to the veth to force TSO off

and NAPI on.

Digging into the failure mode we can see that the connection

is completely stuck after a burst of drops. The sender's snd_nxt

is at sequence number N [1], but the receiver claims to have

received (rcv_nxt) up to N + 3 * MSS [2]. Last piece of the puzzle

is that senders rtx queue is not empty (let's say the block in

the rtx queue is at sequence number N - 4 * MSS [3]).

In this state, sender sends a retransmission from the rtx queue

with a single segment, and sequence numbers N-4*MSS:N-3*MSS [3].

Receiver sees it and responds with an ACK all the way up to

N + 3 * M

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References