{"id":"CVE-2026-90160","revision":"c9e916f4052f4c5e88ad65d072c41061","records":[{"revision":"c9e916f4052f4c5e88ad65d072c41061","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-90160","aliases":[],"title":"lwt_bpf: Restore reserved headroom after xmit program","description":"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 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.","state":0,"publishedAt":"2026-09-17T16:06:51.806+00:00","modifiedAt":"2026-10-19T08:58:58.842+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/core/lwt_bpf.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2\",\n                            \"lessThan\": \"753e5cdcca5474d230d62bb3489e5168ab27c272\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2\",\n                            \"lessThan\": \"c488071c3441fa34f5a87cd6c12ce2cc6304f20e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2\",\n                            \"lessThan\": \"a38c0eb447e2dd0120a2ebcdba470f9505ac8907\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2\",\n                            \"lessThan\": \"de2b2004e16f2930eb689175e2c1998b0a68d499\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2\",\n                            \"lessThan\": \"7d043e24520a273c362be5dd7d9c82796879a49b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2\",\n                            \"lessThan\": \"7cf561843ed0ad57501892a65abb77957e6c800f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2\",\n                            \"lessThan\": \"179a5b2171573d94a25c9aa8e1c9f9ac352ad316\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2\",\n                            \"lessThan\": \"5fe7007aed9ad069b2bd77e5d0c875c64f5c0269\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/core/lwt_bpf.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.10\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.10\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.270\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.221\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.188\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.110\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.52\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.6\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/753e5cdcca5474d230d62bb3489e5168ab27c272","https://git.kernel.org/stable/c/c488071c3441fa34f5a87cd6c12ce2cc6304f20e","https://git.kernel.org/stable/c/a38c0eb447e2dd0120a2ebcdba470f9505ac8907","https://git.kernel.org/stable/c/de2b2004e16f2930eb689175e2c1998b0a68d499","https://git.kernel.org/stable/c/7d043e24520a273c362be5dd7d9c82796879a49b","https://git.kernel.org/stable/c/7cf561843ed0ad57501892a65abb77957e6c800f","https://git.kernel.org/stable/c/179a5b2171573d94a25c9aa8e1c9f9ac352ad316","https://git.kernel.org/stable/c/5fe7007aed9ad069b2bd77e5d0c875c64f5c0269"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-90160","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-90160","identifiers":["CVE-2026-90160"]},"retained":false,"historicalAffected":[]}],"coverage":[]}