{"id":"AZL-104600","summary":"CVE-2026-97965 affecting package kernel 6.6.157.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: initialize _md in vxlan_xmit_one()\n\nIf a VXLAN device is configured with both VXLAN_F_COLLECT_METADATA and\nVXLAN_F_GBP, and a packet is transmitted through it using an external\nip_tunnel_info that lacks the IP_TUNNEL_VXLAN_OPT_BIT flag, md is left\npointing to the uninitialized _md stack variable:\n\n                if (test_bit(IP_TUNNEL_VXLAN_OPT_BIT, info-\u003ekey.tun_flags)) {\n                        if (info-\u003eoptions_len \u003c sizeof(*md))\n                                goto drop;\n                        md = ip_tunnel_info_opts(info);\n                }\n\nBecause IP_TUNNEL_VXLAN_OPT_BIT is not set, md is not updated and remains\npointing to _md. Later, vxlan_build_skb() is called with md, which\neventually calls vxlan_build_gbp_hdr():\n\n        if (vxflags & VXLAN_F_GBP)\n                vxlan_build_gbp_hdr(vxh, md);\n\nInside vxlan_build_gbp_hdr(), md-\u003egbp is read:\n\n        if (!md-\u003egbp)\n                return;\n        gbp = (struct vxlanhdr_gbp *)vxh;\n        ...\n        if (md-\u003egbp & VXLAN_GBP_DONT_LEARN)\n                gbp-\u003edont_learn = 1;\n\nIf the stack contains garbage, this causes:\n1) VXLAN_HF_GBP flag to be spuriously set in the VXLAN header.\n2) gbp-\u003edont_learn and gbp-\u003epolicy_applied to be set from stack bits.\n3) gbp-\u003epolicy_id to receive 16 bits of uninitialized kernel stack data,\n   leaking it onto the wire.\n\nFix this by zero-initializing _md. If IP_TUNNEL_VXLAN_OPT_BIT is not\npresent, md-\u003egbp remains 0, and vxlan_build_gbp_hdr() returns early\nwithout modifying the VXLAN header.","modified":"2026-09-27T05:34:32Z","published":"2026-09-25T11:17:24Z","upstream":["CVE-2026-97965"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97965"}],"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-104600.json"}}],"schema_version":"1.9.0"}