CVE Catalog

CVE-2026-80615

HighCVSS 8.2
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.35%

28th percentile - higher than 28% of all known CVEs

Summary

In the Linux kernel's tun_dst_unclone function, there is a false-positive memcpy overflow warning. The compiler with clang and source fortification estimates that options cannot fit into the structure, even though memory is actually allocated, causing a warning.

Risk Assessment

The warning can be misleading and lead to unnecessary alerts, but does not indicate a real buffer overflow.

Recommendation

Apply a kernel patch that performs the copy in two stages to avoid the false warning.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: net: dst_metadata: fix false-positive memcpy overflow in tun_dst_unclone kmalloc_flex() in metadata_dst_alloc() sets __counted_by for the structure to the options_len, which is then initialized to zero. Later, we're initializing the structure by copying the tunnel info together with the options, and this triggers a warning for a potential memcpy overflow, since the compiler estimates that the options can't fit into the structure, even though the memory for them is actually allocated. memcpy: detected buffer overflow: 104 byte write of buffer size 96 WARNING: CPU: X PID: Y at lib/string_helpers.c:1036 __fortify_report skb_tunnel_info_unclone+0x179/0x190 geneve_xmit+0x7fe/0xe00 The issue is triggered when built with clang and source fortification. Fix that by doing the copy in two stages: first - the main data with the options_len, then the options. This way the correct length should be known at the time of the copy. It would be better if the options_len never changed after allocation, but the allocation code is a little separate from the initialization and it would be awkward and potentially dangerous to return a struct with options_len set to a non-zero value from the metadata_dst_alloc(). Another option would be to use ip_tunnel_info_opts_set(), but it is doing too many unnecessary operations for the use case here.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS