{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80615","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-26T14:34:25.774Z","datePublished":"2026-08-28T06:48:36.315Z","dateUpdated":"2026-08-29T06:21:24.054Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-29T06:21:24.054Z"},"descriptions":[{"lang":"en","value":"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, 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."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","baseScore":8.2,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The bug is reached from geneve_xmit/vxlan_xmit and OVS dev_fill_metadata_dst during overlay packet transmit; remote peers can inject Geneve/VXLAN UDP traffic with tunnel options that later traverse skb_tunnel_info_unclone() on cloud, Kubernetes, and OpenStack/OVN nodes.\nAC:L - On kernels built with CONFIG_FORTIFY_SOURCE and clang, a remote attacker can deterministically trigger the fortified memcpy check by sending Geneve/VXLAN packets carrying non-zero tunnel options that provoke PMTU handling or OVS egress-metadata cloning; no races or victim-specific memory layout are required.\nPR:N - Exploitation requires only that the target host already runs Geneve/VXLAN/OVS overlay netdevs, which is routine in data centers; remote overlay peers and unauthenticated senders whose packets are forwarded through these tunnels need no elevated privileges on the target system.\nUI:N - The fortify warning is triggered automatically during kernel packet transmit or OVS metadata handling with no action required from a local user or administrator beyond normal network operation on an overlay-enabled host.\nS:U - Impact is a kernel fortify WARN/BUG in the host networking stack during tunnel metadata cloning; it does not cross VM, container, or IOMMU security boundaries into another authority domain.\nC:L - No actual out-of-bounds read occurs because fortify halts the memcpy before any real overflow, but __fortify_report() emits a kernel warning and call trace that can disclose limited kernel text/layout information useful for further exploitation.\nI:N - This is a fortify false positive: metadata_dst_alloc() correctly sizes the destination via kmalloc_flex() and fortify aborts before the memcpy executes; there is no memory corruption, arbitrary write, or code-execution primitive.\nA:H - Triggering the fortify check calls __fortify_panic(), which issues WARN then BUG(), causing a kernel oops/panic and immediate denial of service on overlay hosts processing malicious Geneve/VXLAN tunnel-metadata traffic."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/net/dst_metadata.h"],"versions":[{"version":"69050f8d6d075dc01af7a5f2f550a8067510366f","lessThan":"7ce31739fe88a558370135db95bbeec1e7ddfc29","status":"affected","versionType":"git"},{"version":"69050f8d6d075dc01af7a5f2f550a8067510366f","lessThan":"4c6d43db2a4d2cef3921e885cf34798f790d34ea","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/net/dst_metadata.h"],"versions":[{"version":"7.0","status":"affected"},{"version":"0","lessThan":"7.0","status":"unaffected","versionType":"semver"},{"version":"7.1.5","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","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":"7.0","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/7ce31739fe88a558370135db95bbeec1e7ddfc29"},{"url":"https://git.kernel.org/stable/c/4c6d43db2a4d2cef3921e885cf34798f790d34ea"}],"title":"net: dst_metadata: fix false-positive memcpy overflow in tun_dst_unclone","x_generator":{"engine":"bippy-1.2.0"}}}}