CVE-2026-74742
Gravedad CVSS v3.1:
ALTA
Tipo:
No Disponible / Otro tipo
Fecha de publicación:
26/08/2026
Última modificación:
27/08/2026
Descripción
*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br />
<br />
veth: fix queue index used to wake the peer txq in veth_poll<br />
<br />
veth_poll() derives the index of the peer TX queue to wake from<br />
rq->xdp_rxq.queue_index. That field is only initialized by<br />
xdp_rxq_info_reg() in veth_enable_xdp_range(), which runs only when an<br />
XDP program is attached. On the plain GRO/NAPI path<br />
(veth_napi_enable_range()) xdp_rxq_info_reg() is never called, so<br />
queue_index stays 0 for every queue, as priv->rq is zero-allocated.<br />
<br />
So in a multi-queue setup with GRO enabled and no XDP program attached,<br />
every NAPI instance looks at the peer&#39;s TX queue 0. If veth_xmit() stops<br />
peer TX queue 1 because the ptr_ring is full (NETDEV_TX_BUSY), nothing<br />
ever wakes it again: the poller draining queue 1 wakes queue 0 instead.<br />
veth implements no ndo_tx_timeout, so the netdev watchdog does not kick<br />
in either, and the queue stays stopped indefinitely.<br />
<br />
Derive the index from the position of the rq within priv->rq instead,<br />
which is correct regardless of whether XDP was ever enabled.<br />
<br />
Scripts to reproduce the stall are available at<br />
https://github.com/netoptimizer/veth-backpressure-performance-testing
Impacto
Puntuación base 3.x
7.50
Gravedad 3.x
ALTA



