vsock/virtio: account only unread bytes in read_skb()

Summary

In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: account only unread bytes in read_skb() After a partial stream receive, rx_bytes tracks the unread suffix while buf_used and peer credit still cover the whole packet. virtio_transport_read_skb() dequeues that packet but passes pkt_len for both counters, underflowing rx_bytes. On a connected CID_LOCAL stream with an SK_SKB verdict, a 40-byte read from a 100-byte packet made SIOCINQ report -40, an empty recv return ELOOP, and poll report the empty socket readable. After verdict detach, receiving 40 bytes wrapped the counter to zero and hid those queued bytes until one more byte arrived. The fixed run kept the counter balanced and exposed all queued data immediately. This was found during an LLM-assisted manual source audit of VSOCK receive accounting while re-evaluating virtio_transport_read_skb() after CVE-2024-50169. Subtract only skb->len minus the VSOCK offset from rx_bytes. Retain the full packet length for buf_used and peer credit.

Timeline

1. Oct 23, 2026, 12:23 PM UTCCVE published
2. Oct 23, 2026, 12:45 PM UTCFirst seen by cve.now

Affected versions

• Linux Linux

  From 7893a41deaf28b53036d4ea7cd9f7d54e8874dfc · fixed in e4a0028b0d54b2c45e1dc8c0dd95fe3e9236f55b; From 45ca7e9f0730ae36fc610e675b990e9cc9ca0714 · fixed in 38bad3930b1185dd6c98db3dd342ddc123c6f3ef; From 45ca7e9f0730ae36fc610e675b990e9cc9ca0714 · fixed in dd4b2f88ee517f9629d0d3dbfced02ffbc33e2dc; From 45ca7e9f0730ae36fc610e675b990e9cc9ca0714 · fixed in a463f55c791b96cfd12df8b10ea737d45c80bb18; From 6.12.34 · fixed in 6.12.113; From 6.15.3 · fixed in 6.16

• Linux Linux

  6.16

• KernelLinux

  fixed in 6.12.113; From 6.13.0 · fixed in 6.18.57; From 6.16.0 · fixed in 7.2.11

References 4