{"id":"CVE-2026-80615","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: dst_metadata: fix false-positive memcpy overflow in tun_dst_unclone\n\nkmalloc_flex() in metadata_dst_alloc() sets __counted_by for the\nstructure to the options_len,…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: dst_metadata: fix false-positive memcpy overflow in tun_dst_unclone\n\nkmalloc_flex() in metadata_dst_alloc() sets __counted_by for the\nstructure to the options_len,…","severity":"high","cvss":8.2,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","published":"2026-08-28","updated":"2026-08-29","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-80615","references":[{"url":"https://git.kernel.org/stable/c/4c6d43db2a4d2cef3921e885cf34798f790d34ea","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7ce31739fe88a558370135db95bbeec1e7ddfc29","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00489,"epssPercentile":0.39504,"ingestedAt":"2026-08-29T23:43:56.241Z","slug":"CVE-2026-80615","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: dst_metadata: fix false-positive memcpy overflow in tun_dst_unclone\n\nkmalloc_flex() in metadata_dst_alloc() sets __counted_by for the\nstructure to the options_len, which is then initialized to zero.\nLater, we're initializing the structure by copying the tunnel info\ntogether with the options, and this triggers a warning for a potential\nmemcpy overflow, since the compiler estimates that the options can't\nfit into the structure, even though the memory for them is actually\nallocated.\n\n memcpy: detected buffer overflow: 104 byte write of buffer size 96\n WARNING: CPU: X PID: Y at lib/string_helpers.c:1036 __fortify_report\n  skb_tunnel_info_unclone+0x179/0x190\n  geneve_xmit+0x7fe/0xe00\n\nThe issue is triggered when built with clang and source fortification.\n\nFix that by doing the copy in two stages: first - the main data with\nthe options_len, then the options.  This way the correct length should\nbe known at the time of the copy.\n\nIt would be better if the options_len never changed after allocation,\nbut the allocation code is a little separate from the initialization\nand it would be awkward and potentially dangerous to return a struct\nwith options_len set to a non-zero value from the metadata_dst_alloc().\n\nAnother option would be to use ip_tunnel_info_opts_set(), but it is\ndoing too many unnecessary operations for the use case here.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":45.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}