--- id: CVE-2024-35944 title: |- In the Linux kernel, the following vulnerability has been resolved: VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host() Syzkaller hit 'WARNING in dg_dispatch_as_host' bug. memcpy: detected field-spanning write (size 56) of si… summary: |- In the Linux kernel, the following vulnerability has been resolved: VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host() Syzkaller hit 'WARNING in dg_dispatch_as_host' bug. memcpy: detected field-spanning write (size 56) of si… severity: medium cvss: 5.5 cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H' vendor: linux product: linux_kernel affected: - linux_kernel < 4.19.312 - 'linux_kernel >= 4.20, < 5.4.274' - 'linux_kernel >= 5.5, < 5.10.215' - 'linux_kernel >= 5.11, < 5.15.155' - 'linux_kernel >= 5.16, < 6.1.86' - 'linux_kernel >= 6.2, < 6.6.27' - 'linux_kernel >= 6.7, < 6.8.6' - debian_linux = 10.0 patched: - linux_kernel 6.8.6 published: '2024-05-19' updated: '2026-10-15' sourceUpdated: '2026-10-15T01:17:54.707' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2024-35944' references: - url: 'https://git.kernel.org/stable/c/130b0cd064874e0d0f58e18fb00e6f3993e90c74' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/19b070fefd0d024af3daa7329cbc0d00de5302ec' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/491a1eb07c2bd8841d63cb5263455e185be5866f' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/ad78c5047dc4076d0b3c4fad4f42ffe9c86e8100' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/dae70a57565686f16089737adb8ac64471570f73' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/e87bb99d2df6512d8ee37a5d63d2ca9a39a8c051' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/f15eca95138b3d4ec17b63c3c1937b0aa0d3624b' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/feacd430b42bbfa9ab3ed9e4f38b86c43e348c75' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/130b0cd064874e0d0f58e18fb00e6f3993e90c74' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/19b070fefd0d024af3daa7329cbc0d00de5302ec' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/491a1eb07c2bd8841d63cb5263455e185be5866f' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/ad78c5047dc4076d0b3c4fad4f42ffe9c86e8100' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/dae70a57565686f16089737adb8ac64471570f73' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/e87bb99d2df6512d8ee37a5d63d2ca9a39a8c051' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/f15eca95138b3d4ec17b63c3c1937b0aa0d3624b' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/feacd430b42bbfa9ab3ed9e4f38b86c43e348c75' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://cert-portal.siemens.com/productcert/html/ssa-265688.html' label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e - url: 'https://cert-portal.siemens.com/productcert/html/ssa-398330.html' label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e tags: - nvd - cve.org epss: 0.00234 epssPercentile: 0.14283 ingestedAt: '2026-10-15T03:30:12.691Z' ssvc: exploitation: none automatable: 'no' technicalImpact: partial timestamp: '2024-05-20T14:30:02.800597Z' --- ## Overview In the Linux kernel, the following vulnerability has been resolved: VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host() Syzkaller hit 'WARNING in dg_dispatch_as_host' bug. memcpy: detected field-spanning write (size 56) of single field "&dg_info->msg" at drivers/misc/vmw_vmci/vmci_datagram.c:237 (size 24) WARNING: CPU: 0 PID: 1555 at drivers/misc/vmw_vmci/vmci_datagram.c:237 dg_dispatch_as_host+0x88e/0xa60 drivers/misc/vmw_vmci/vmci_datagram.c:237 Some code commentry, based on my understanding: 544 #define VMCI_DG_SIZE(_dg) (VMCI_DG_HEADERSIZE + (size_t)(_dg)->payload_size) /// This is 24 + payload_size memcpy(&dg_info->msg, dg, dg_size); Destination = dg_info->msg ---> this is a 24 byte structure(struct vmci_datagram) Source = dg --> this is a 24 byte structure (struct vmci_datagram) Size = dg_size = 24 + payload_size {payload_size = 56-24 =32} -- Syzkaller managed to set payload_size to 32. 35 struct delayed_datagram_info { 36 struct datagram_entry *entry; 37 struct work_struct work; 38 bool in_dg_host_queue; 39 /* msg and msg_payload must be together. */ 40 struct vmci_datagram msg; 41 u8 msg_payload[]; 42 }; So those extra bytes of payload are copied into msg_payload[], a run time warning is seen while fuzzing with Syzkaller. One possible way to fix the warning is to split the memcpy() into two parts -- one -- direct assignment of msg and second taking care of payload. Gustavo quoted: "Under FORTIFY_SOURCE we should not copy data across multiple members in a structure." ## Affected - `linux_kernel < 4.19.312` - `linux_kernel >= 4.20, < 5.4.274` - `linux_kernel >= 5.5, < 5.10.215` - `linux_kernel >= 5.11, < 5.15.155` - `linux_kernel >= 5.16, < 6.1.86` - `linux_kernel >= 6.2, < 6.6.27` - `linux_kernel >= 6.7, < 6.8.6` - `debian_linux = 10.0` ## Remediation Upgrade past the affected range: - `linux_kernel 6.8.6`