{"id":"CVE-2026-23057","state":"PUBLISHED","title":"vsock/virtio: Coalesce only linear skb","description":"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) > 0\nguarantees last_skb is linear.","publishedAt":"2026-02-04T16:07:40.550Z","updatedAt":"2026-05-11T21:59:10.131Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"581512a6dc939ef122e49336626ae159f3b8a345","status":"affected","lessThan":"568e9cd8ed7ca9bf748c7687ba6501f29d30e59f","versionType":"git"},{"version":"581512a6dc939ef122e49336626ae159f3b8a345","status":"affected","lessThan":"63ef9b300bd09e24c57050c5dbe68feedce42e72","versionType":"git"},{"version":"581512a6dc939ef122e49336626ae159f3b8a345","status":"affected","lessThan":"0386bd321d0f95d041a7b3d7b07643411b044a96","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/vmw_vsock/virtio_transport_common.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.7","versionType":"semver"},{"version":"6.12.68","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.8","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/vmw_vsock/virtio_transport_common.c"]}],"references":["https://git.kernel.org/stable/c/568e9cd8ed7ca9bf748c7687ba6501f29d30e59f","https://git.kernel.org/stable/c/63ef9b300bd09e24c57050c5dbe68feedce42e72","https://git.kernel.org/stable/c/0386bd321d0f95d041a7b3d7b07643411b044a96"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:21.040Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/23xxx/CVE-2026-23057.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23057","state":"PUBLISHED","datePublished":"2026-02-04T16:07:40.550Z","dateUpdated":"2026-05-11T21:59:10.131Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-01-13T15:37:45.951Z"},"containers":{"cna":{"title":"vsock/virtio: Coalesce only linear skb","descriptions":[{"lang":"en","value":"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) > 0\nguarantees last_skb is linear."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"581512a6dc939ef122e49336626ae159f3b8a345","status":"affected","lessThan":"568e9cd8ed7ca9bf748c7687ba6501f29d30e59f","versionType":"git"},{"version":"581512a6dc939ef122e49336626ae159f3b8a345","status":"affected","lessThan":"63ef9b300bd09e24c57050c5dbe68feedce42e72","versionType":"git"},{"version":"581512a6dc939ef122e49336626ae159f3b8a345","status":"affected","lessThan":"0386bd321d0f95d041a7b3d7b07643411b044a96","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/vmw_vsock/virtio_transport_common.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.7","versionType":"semver"},{"version":"6.12.68","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.8","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/vmw_vsock/virtio_transport_common.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/568e9cd8ed7ca9bf748c7687ba6501f29d30e59f"},{"url":"https://git.kernel.org/stable/c/63ef9b300bd09e24c57050c5dbe68feedce42e72"},{"url":"https://git.kernel.org/stable/c/0386bd321d0f95d041a7b3d7b07643411b044a96"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T21:59:10.131Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.68"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.18.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.19"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}