{"id":"CVE-2026-23057","summary":"vsock/virtio: Coalesce only linear skb","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.","modified":"2026-04-02T17:29:28.045319Z","published":"2026-02-04T16:07:40.550Z","related":["SUSE-SU-2026:0962-1","SUSE-SU-2026:1081-1","SUSE-SU-2026:20667-1","SUSE-SU-2026:20720-1","SUSE-SU-2026:20838-1","SUSE-SU-2026:20845-1","SUSE-SU-2026:20876-1","SUSE-SU-2026:20931-1","openSUSE-SU-2026:20416-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23057.json","cna_assigner":"Linux"},"references":[{"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"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23057.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23057"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"581512a6dc939ef122e49336626ae159f3b8a345"},{"fixed":"568e9cd8ed7ca9bf748c7687ba6501f29d30e59f"},{"fixed":"63ef9b300bd09e24c57050c5dbe68feedce42e72"},{"fixed":"0386bd321d0f95d041a7b3d7b07643411b044a96"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23057.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.68"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23057.json"}}],"schema_version":"1.7.5"}