GHSA-2725-MXXG-W826
Vulnerability from github – Published: 2026-02-04 18:30 – Updated: 2026-02-04 18:30In 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": [],
"aliases": [
"CVE-2026-23057"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-02-04T17:16:16Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock/virtio: Coalesce only linear skb\n\nvsock/virtio common tries to coalesce buffers in rx queue: if a linear skb\n(with a spare tail room) is followed by a small skb (length limited by\nGOOD_COPY_LEN = 128), an attempt is made to join them.\n\nSince the introduction of MSG_ZEROCOPY support, assumption that a small skb\nwill always be linear is incorrect. In the zerocopy case, data is lost and\nthe linear skb is appended with uninitialized kernel memory.\n\nOf all 3 supported virtio-based transports, only loopback-transport is\naffected. G2H virtio-transport rx queue operates on explicitly linear skbs;\nsee virtio_vsock_alloc_linear_skb() in virtio_vsock_rx_fill(). H2G\nvhost-transport may allocate non-linear skbs, but only for sizes that are\nnot considered for coalescence; see PAGE_ALLOC_COSTLY_ORDER in\nvirtio_vsock_alloc_skb().\n\nEnsure only linear skbs are coalesced. Note that skb_tailroom(last_skb) \u003e 0\nguarantees last_skb is linear.",
"id": "GHSA-2725-mxxg-w826",
"modified": "2026-02-04T18:30:43Z",
"published": "2026-02-04T18:30:43Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23057"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0386bd321d0f95d041a7b3d7b07643411b044a96"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/568e9cd8ed7ca9bf748c7687ba6501f29d30e59f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/63ef9b300bd09e24c57050c5dbe68feedce42e72"
}
],
"schema_version": "1.4.0",
"severity": []
}
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