CVE Catalog

CVE-2026-74742

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.47%

38th percentile - higher than 38% of all known CVEs

Summary

In the Linux kernel, the veth interface has a bug in veth_poll that uses an incorrect queue index to wake the peer TX queue. Without an XDP program, the index remains 0, which can lead to a permanent stall of the TX queue and loss of transmission.

Risk Assessment

The vulnerability can cause permanent blocking of data transmission on veth interfaces, leading to unavailability of network services and potential downtime.

Recommendation

Apply the kernel patch that correctly derives the queue index based on the position in priv->rq, and update the system.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: veth: fix queue index used to wake the peer txq in veth_poll veth_poll() derives the index of the peer TX queue to wake from rq->xdp_rxq.queue_index. That field is only initialized by xdp_rxq_info_reg() in veth_enable_xdp_range(), which runs only when an XDP program is attached. On the plain GRO/NAPI path (veth_napi_enable_range()) xdp_rxq_info_reg() is never called, so queue_index stays 0 for every queue, as priv->rq is zero-allocated. So in a multi-queue setup with GRO enabled and no XDP program attached, every NAPI instance looks at the peer's TX queue 0. If veth_xmit() stops peer TX queue 1 because the ptr_ring is full (NETDEV_TX_BUSY), nothing ever wakes it again: the poller draining queue 1 wakes queue 0 instead. veth implements no ndo_tx_timeout, so the netdev watchdog does not kick in either, and the queue stays stopped indefinitely. Derive the index from the position of the rq within priv->rq instead, which is correct regardless of whether XDP was ever enabled. Scripts to reproduce the stall are available at https://github.com/netoptimizer/veth-backpressure-performance-testing

Vulnerability data from NVD (NIST) · CISA KEV · EPSS