{"id":"CVE-2026-90160","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nlwt_bpf: Restore reserved headroom after xmit program\n\nip_finish_output2() expands an skb to LL_RESERVED_SPACE(dev) before LWT\nxmit","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nlwt_bpf: Restore reserved headroom after xmit program\n\nip_finish_output2() expands an skb to LL_RESERVED_SPACE(dev) before LWT\nxmit. An LWT_XMIT BPF program can then mo…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 753e5cdcca5474d230d62bb3489e5168ab27c272","Linux >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < c488071c3441fa34f5a87cd6c12ce2cc6304f20e","Linux >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < a38c0eb447e2dd0120a2ebcdba470f9505ac8907","Linux >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < de2b2004e16f2930eb689175e2c1998b0a68d499","Linux >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 7d043e24520a273c362be5dd7d9c82796879a49b","Linux >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 7cf561843ed0ad57501892a65abb77957e6c800f","Linux >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 179a5b2171573d94a25c9aa8e1c9f9ac352ad316","Linux >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 5fe7007aed9ad069b2bd77e5d0c875c64f5c0269","Linux 4.10"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T17:17:09.190","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90160","references":[{"url":"https://git.kernel.org/stable/c/179a5b2171573d94a25c9aa8e1c9f9ac352ad316","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5fe7007aed9ad069b2bd77e5d0c875c64f5c0269","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/753e5cdcca5474d230d62bb3489e5168ab27c272","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7cf561843ed0ad57501892a65abb77957e6c800f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7d043e24520a273c362be5dd7d9c82796879a49b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a38c0eb447e2dd0120a2ebcdba470f9505ac8907","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c488071c3441fa34f5a87cd6c12ce2cc6304f20e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/de2b2004e16f2930eb689175e2c1998b0a68d499","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-17T16:21:47.872Z","epss":0.0021,"epssPercentile":0.11542,"slug":"CVE-2026-90160","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nlwt_bpf: Restore reserved headroom after xmit program\n\nip_finish_output2() expands an skb to LL_RESERVED_SPACE(dev) before LWT\nxmit. An LWT_XMIT BPF program can then modify the skb head and still\nreturn BPF_OK, so bpf_xmit() rechecks the remaining headroom before the\nskb continues to neighbour output.\n\nThat recheck uses dst->dev->hard_header_len. This is not enough for the\nneighbour cached-header path: neigh_hh_output() copies the cached hardware\nheader using the aligned hh_cache size, HH_DATA_MOD for short headers or\nHH_DATA_ALIGN(hh_len) otherwise.\n\nOn Ethernet, hard_header_len is 14 but the cached copy needs 16 bytes. If\nan LWT_XMIT BPF program calls bpf_skb_change_head(skb, 1, 0), the skb can\nstill have 15 bytes of headroom after the program. The existing check\naccepts that, after which neigh_hh_output() hits its headroom warning and\ndrops the skb.\n\nUse LL_RESERVED_SPACE(dst->dev) in the post-BPF headroom check to match\nthe reservation made before LWT xmit.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}