{
  "cveId": "CVE-2026-99088",
  "url": "https://patchblox.com/security/cve/CVE-2026-99088",
  "summary": "CVE-2026-99088 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-99088, released October 27, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "net: openvswitch: validate transport header presence in set_ipv6_addr",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  net: openvswitch: validate transport header presence in set_ipv6_addr  When executing IPv6 address rewrite actions on IPv6 fragments, set_ipv6_addr() calls update_ipv6_checksum(). If parse_ipv6hdr() processes a non-first IPv6 fragment, it sets key-\u003Eip.proto to NEXTHDR_FRAGMENT and returns early without calling skb_set_transport_header().  update_ipv6_checksum() unconditionally evaluates skb_transport_offset() on entry before checking l4_proto.  Because skb-\u003Etransport_header is uninitialized, this triggers a warning under CONFIG_DEBUG_NET=y although it is completely harmless.  Fix this by returning early in update_ipv6_checksum() if l4_proto is NEXTHDR_FRAGMENT. This avoids reading the uninitialized transport offset for fragments while preserving the debug warning for any other protocol where the transport header is unexpectedly missing.  See the syzbot trace:  !skb_transport_header_was_set(skb) WARNING: ./include/linux/skbuff.h:3075 at skb_transport_header include/linux/skbuff.h:3075 [inline], CPU#1: syz-executor463/5635 WARNING: ./include/linux/skbuff.h:3075 at skb_transport_offset include/linux/skbuff.h:3250 [inline], CPU#1: syz-executor463/5635 WARNING: ./include/linux/skbuff.h:3075 at update_ipv6_checksum net/openvswitch/actions.c:361 [inline], CPU#1: syz-executor463/5635 WARNING: ./include/linux/skbuff.h:3075 at set_ipv6_addr\u002B0x462/0x660 net/openvswitch/actions.c:399, CPU#1: syz-executor463/5635 [...] RIP: 0010:skb_transport_header include/linux/skbuff.h:3075 [inline] RIP: 0010:skb_transport_offset include/linux/skbuff.h:3250 [inline] RIP: 0010:update_ipv6_checksum net/openvswitch/actions.c:361 [inline] RIP: 0010:set_ipv6_addr\u002B0x462/0x660 net/openvswitch/actions.c:399 [...] Call Trace:  \u003CTASK\u003E  set_ipv6 net/openvswitch/actions.c:531 [inline]  do_execute_actions\u002B0x557e/0x8600 net/openvswitch/actions.c:1366  ovs_execute_actions\u002B0xde/0x520 net/openvswitch/actions.c:1592  ovs_packet_cmd_execute\u002B0xb4f/0xf10 net/openvswitch/datapath.c:705  genl_family_rcv_msg_doit\u002B0x233/0x340 net/netlink/genetlink.c:1114  genl_rcv_msg\u002B0x614/0x7a0 net/netlink/genetlink.c:1209  netlink_rcv_skb\u002B0x226/0x4a0 net/netlink/af_netlink.c:2572  genl_rcv\u002B0x28/0x40 net/netlink/genetlink.c:1218  netlink_unicast\u002B0x7bd/0x940 net/netlink/af_netlink.c:1361  netlink_sendmsg\u002B0x813/0xb40 net/netlink/af_netlink.c:1916  sock_sendmsg_nosec\u002B0x14e/0x190 net/socket.c:800",
  "published": "2026-10-26T15:16:47Z",
  "severity": "Low",
  "cvss": 2.3,
  "epss": 0.00172,
  "epssPercentile": 0.06679,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-99088",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.113-1",
      "fix": "DEBIAN-CVE-2026-99088",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99088",
      "released": "2026-10-27T21:14:52Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.11-1",
      "fix": "DEBIAN-CVE-2026-99088",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99088",
      "released": "2026-10-27T21:14:52Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}