CVE-2026-99062 vsock/virtio: account only unread bytes in read_skb()
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-99062?
CVE-2026-99062 is a vulnerability in Linux, published on 23 Oct 2026.
Official description
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.
Which versions are affected by CVE-2026-99062?
How do I fix CVE-2026-99062?
Upgrade to a fixed version.
Is CVE-2026-99062 being exploited?
There is no known exploitation of CVE-2026-99062 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-99062, DEBIAN-CVE-2026-99062, GHSA-q643-38mv-p69j, UBUNTU-CVE-2026-99062.