{"id":"AZL-102935","summary":"CVE-2026-90160 affecting package kernel 6.6.150.1-1","details":"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-\u003edev-\u003ehard_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-\u003edev) in the post-BPF headroom check to match\nthe reservation made before LWT xmit.","modified":"2026-09-18T14:18:02.996446497Z","published":"2026-09-17T17:17:09Z","upstream":["CVE-2026-90160"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90160"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-102935.json"}}],"schema_version":"1.9.0"}