{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-39718", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.117Z", "datePublished": "2025-09-05T17:21:25.959Z", "dateUpdated": "2026-08-05T12:04:50.190Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:04:50.190Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock/virtio: Validate length in packet header before skb_put()\n\nWhen receiving a vsock packet in the guest, only the virtqueue buffer\nsize is validated prior to virtio_vsock_skb_rx_put(). Unfortunately,\nvirtio_vsock_skb_rx_put() uses the length from the packet header as the\nlength argument to skb_put(), potentially resulting in SKB overflow if\nthe host has gone wonky.\n\nValidate the length as advertised by the packet header before calling\nvirtio_vsock_skb_rx_put()." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.4, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The attack surface is the virtio-vsock RX virtqueue, which is host/hypervisor-local to the guest rather than network-reachable; vsock carries no routed network traffic. This matches the kernel CNA convention of AV:L for malicious-virtio-backend attacks on guest drivers.\nAC:L - The backend simply writes an arbitrary 32-bit value into the packet header's len field; no race, no memory-layout dependency, and the wraparound window that defeats skb_over_panic() is a fixed, deterministic 44-value range. Every trigger condition is fully under the attacker's control.\nPR:N - No privileges exist in the vulnerable component — the guest kernel — for the attacker to hold; virtio_transport_rx_work() consumes the buffer from a workqueue as soon as the device completes it, with no guest socket, user, or capability involved. Userspace VMMs (Firecracker, crosvm, vhost-user-vsock) are deliberately deprivileged, and under SEV-SNP/TDX/CCA the host is untrusted by design.\nUI:N - The RX work item processes the malicious buffer automatically on device completion, and the vsockmon tap path runs before any socket lookup. No guest user opens a socket, reads data, or performs any action.\nS:U - The vulnerable component and every impacted resource are the guest kernel and its own userspace, which share one security authority. Consistent with the S:U precedent for device→guest virtio driver bugs (CVE-2026-46123, CVE-2026-64456, CVE-2026-64490); S:C in this subsystem has been reserved for guest→host direction.\nC:H - A header len exceeding the bytes the device actually wrote makes skb_put() expose uninitialized kmalloc-8k slab contents, which recvmsg() copies straight to guest userspace, and the u32-wrap case leaves skb->len at ~4 GiB so skb_copy_datagram_iter() reads essentially unbounded guest kernel memory. Repeatable per packet with heap grooming, this is an arbitrary kernel-memory read.\nI:H - The wraparound bypasses skb_over_panic() and leaves a corrupted skb whose len/tail are desynchronized from the allocation; virtio_transport_build_skb() then truncates the size_t allocation size to 75 bytes and performs skb_put_data() of 0xFFFFFFFF, an unbounded out-of-bounds memcpy write out of a small slab object. Combined with the read primitive this is a heap-corruption primitive suitable for control-flow hijack in the guest.\nA:H - Any header len outside the narrow wrap window drives skb->tail past skb->end, hitting skb_over_panic() → BUG() in the virtio_vsock workqueue, and the wrap path instead faults on a multi-gigabyte copy. Either way the guest kernel oopses or panics, triggerable at will and repeatedly." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/vmw_vsock/virtio_transport.c" ], "versions": [ { "version": "baddcc2c71572968cdaeee1c4ab3dc0ad90fa765", "lessThan": "969b06bd8b7560efb100a34227619e7d318fbe05", "status": "affected", "versionType": "git" }, { "version": "71dc9ec9ac7d3eee785cdc986c3daeb821381e20", "lessThan": "ee438c492b2e0705d819ac0e25d04fae758d8f8f", "status": "affected", "versionType": "git" }, { "version": "71dc9ec9ac7d3eee785cdc986c3daeb821381e20", "lessThan": "faf332a10372390ce65d0b803888f4b25a388335", "status": "affected", "versionType": "git" }, { "version": "71dc9ec9ac7d3eee785cdc986c3daeb821381e20", "lessThan": "676f03760ca1d69c2470cef36c44dc152494b47c", "status": "affected", "versionType": "git" }, { "version": "71dc9ec9ac7d3eee785cdc986c3daeb821381e20", "lessThan": "0dab92484474587b82e8e0455839eaf5ac7bf894", "status": "affected", "versionType": "git" }, { "version": "6.1.63", "lessThan": "6.1.149", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/vmw_vsock/virtio_transport.c" ], "versions": [ { "version": "6.3", "status": "affected" }, { "version": "0", "lessThan": "6.3", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.149", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.103", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.44", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16.4", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.63", "versionEndExcluding": "6.1.149" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.6.103" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.12.44" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.16.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.17" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/969b06bd8b7560efb100a34227619e7d318fbe05" }, { "url": "https://git.kernel.org/stable/c/ee438c492b2e0705d819ac0e25d04fae758d8f8f" }, { "url": "https://git.kernel.org/stable/c/faf332a10372390ce65d0b803888f4b25a388335" }, { "url": "https://git.kernel.org/stable/c/676f03760ca1d69c2470cef36c44dc152494b47c" }, { "url": "https://git.kernel.org/stable/c/0dab92484474587b82e8e0455839eaf5ac7bf894" } ], "title": "vsock/virtio: Validate length in packet header before skb_put()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T17:42:44.024Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-05-12T12:06:34.737Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC CN 4100", "versions": [ { "status": "affected", "version": "0", "lessThan": "V5.0", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-032379.html" } ] } ] } }