cbcvebase.
CVE-2026-23057
published 2026-02-04

CVE-2026-23057: In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: Coalesce only linear skb vsock/virtio common tries to coalesce buffers in rx…

PriorityP420high7.8
EPSS
0.17%
6.2th percentile
In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: Coalesce only linear skb vsock/virtio common tries to coalesce buffers in rx queue: if a linear skb (with a spare tail room) is followed by a small skb (length limited by GOOD_COPY_LEN = 128), an attempt is made to join them. Since the introduction of MSG_ZEROCOPY support, assumption that a small skb will always be linear is incorrect. In the zerocopy case, data is lost and the linear skb is appended with uninitialized kernel memory. Of all 3 supported virtio-based transports, only loopback-transport is affected. G2H virtio-transport rx queue operates on explicitly linear skbs; see virtio_vsock_alloc_linear_skb() in virtio_vsock_rx_fill(). H2G vhost-transport may allocate non-linear skbs, but only for sizes that are not considered for coalescence; see PAGE_ALLOC_COSTLY_ORDER in virtio_vsock_alloc_skb(). Ensure only linear skbs are coalesced. Note that skb_tailroom(last_skb) > 0 guarantees last_skb is linear.

Affected

39 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.18.8-1 (forky)linux 6.18.8-1 (forky)
linuxlinux
linuxlinux>= 581512a6dc939ef122e49336626ae159f3b8a345 < 568e9cd8ed7ca9bf748c7687ba6501f29d30e59f568e9cd8ed7ca9bf748c7687ba6501f29d30e59f
linuxlinux>= 581512a6dc939ef122e49336626ae159f3b8a345 < 63ef9b300bd09e24c57050c5dbe68feedce42e7263ef9b300bd09e24c57050c5dbe68feedce42e72
linuxlinux>= 581512a6dc939ef122e49336626ae159f3b8a345 < 0386bd321d0f95d041a7b3d7b07643411b044a960386bd321d0f95d041a7b3d7b07643411b044a96
linuxlinux_kernel>= 0 < 6.12.69-16.12.69-1
linuxlinux_kernel>= 0 < 6.18.8-16.18.8-1
linuxlinux_kernel>= 6.13.0 < 6.18.86.18.8
linuxlinux_kernel>= 6.7.0 < 6.12.686.12.68
ubuntulinux
ubuntulinux-aws
ubuntulinux-aws-fips
ubuntulinux-azure
ubuntulinux-azure-6.17
ubuntulinux-azure-6.8
ubuntulinux-azure-fde-6.17
ubuntulinux-azure-fips
ubuntulinux-fips
ubuntulinux-gcp
ubuntulinux-gcp-6.17
ubuntulinux-gcp-fips
ubuntulinux-gke
ubuntulinux-gkeop
ubuntulinux-ibm
ubuntulinux-ibm-6.8

CVSS provenance

vendor_ubuntu7.8HIGH
vendor_redhat5.5MEDIUM
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