{"id":"AZL-111119","summary":"CVE-2026-99088 affecting package kernel 6.6.157.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: validate transport header presence in set_ipv6_addr\n\nWhen executing IPv6 address rewrite actions on IPv6 fragments,\nset_ipv6_addr() calls update_ipv6_checksum(). If parse_ipv6hdr()\nprocesses a non-first IPv6 fragment, it sets key-\u003eip.proto to\nNEXTHDR_FRAGMENT and returns early without calling\nskb_set_transport_header().\n\nupdate_ipv6_checksum() unconditionally evaluates skb_transport_offset()\non entry before checking l4_proto.  Because skb-\u003etransport_header is\nuninitialized, this triggers a warning under CONFIG_DEBUG_NET=y although\nit is completely harmless.\n\nFix this by returning early in update_ipv6_checksum() if l4_proto is\nNEXTHDR_FRAGMENT. This avoids reading the uninitialized transport offset\nfor fragments while preserving the debug warning for any other protocol\nwhere the transport header is unexpectedly missing.\n\nSee the syzbot trace:\n\n!skb_transport_header_was_set(skb)\nWARNING: ./include/linux/skbuff.h:3075 at skb_transport_header include/linux/skbuff.h:3075 [inline], CPU#1: syz-executor463/5635\nWARNING: ./include/linux/skbuff.h:3075 at skb_transport_offset include/linux/skbuff.h:3250 [inline], CPU#1: syz-executor463/5635\nWARNING: ./include/linux/skbuff.h:3075 at update_ipv6_checksum net/openvswitch/actions.c:361 [inline], CPU#1: syz-executor463/5635\nWARNING: ./include/linux/skbuff.h:3075 at set_ipv6_addr+0x462/0x660 net/openvswitch/actions.c:399, CPU#1: syz-executor463/5635\n[...]\nRIP: 0010:skb_transport_header include/linux/skbuff.h:3075 [inline]\nRIP: 0010:skb_transport_offset include/linux/skbuff.h:3250 [inline]\nRIP: 0010:update_ipv6_checksum net/openvswitch/actions.c:361 [inline]\nRIP: 0010:set_ipv6_addr+0x462/0x660 net/openvswitch/actions.c:399\n[...]\nCall Trace:\n \u003cTASK\u003e\n set_ipv6 net/openvswitch/actions.c:531 [inline]\n do_execute_actions+0x557e/0x8600 net/openvswitch/actions.c:1366\n ovs_execute_actions+0xde/0x520 net/openvswitch/actions.c:1592\n ovs_packet_cmd_execute+0xb4f/0xf10 net/openvswitch/datapath.c:705\n genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114\n genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209\n netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2572\n genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218\n netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1361\n netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1916\n sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800","modified":"2026-10-27T14:16:06.830172014Z","published":"2026-10-26T15:16:47Z","upstream":["CVE-2026-99088"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99088"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.157.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-111119.json"}}],"schema_version":"1.9.2"}