{"cve":{"cve_id":"CVE-2026-52940","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":null,"epss_percentile":null,"epss_as_of":null,"description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntun: zero the whole vnet header in tun_put_user()\n\ntun_put_user() declares an on-stack struct virtio_net_hdr_v1_hash_tunnel\nwithout zeroing it. For a non-tunnel skb, virtio_net_hdr_tnl_from_skb()\nonly initializes the first 10 bytes (sizeof(struct virtio_net_hdr)),\nleaving bytes 10..23 (num_buffers and the hash/tunnel fields) as stack\ngarbage.\n\nAn unprivileged user can set the vnet header size to 24 with\nTUNSETVNETHDRSZ, so __tun_vnet_hdr_put() copies all 24 bytes of the\npartially-initialized struct to userspace, leaking 14 bytes of kernel\nstack on every read of a non-tunnel packet.\n\nFix it the same way tun_get_user() already does by zeroing the whole\nheader right after declaration.","published_at":"2026-06-24T07:14:29.281000Z","last_modified_at":null,"cvss_v3_score":null,"cvss_v3_vector":null,"cvss_v3_severity":null,"cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":null,"nvd_references":["https://git.kernel.org/stable/c/5fd1fa5a4254bfdd70571c77f5e3bcb4e43738d5","https://git.kernel.org/stable/c/585cb85e9a29185be05f326369573c2663cf4380","https://git.kernel.org/stable/c/7f2fcff15e99bb852f6967396ed12b38376e2c8d"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-28T17:55:22.518073Z","updated_at":"2026-06-28T23:30:49.890169Z"},"effective_severity":null,"badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":null,"metrics":[]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"288f30435132d2f9e7a29ec9b9745a4f9dc7fd37","version_start_inclusive":true,"version_end":"5fd1fa5a4254bfdd70571c77f5e3bcb4e43738d5","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:288f30435132d2f9e7a29ec9b9745a4f9dc7fd37:5fd1fa5a4254bfdd70571c77f5e3bcb4e43738d5"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"288f30435132d2f9e7a29ec9b9745a4f9dc7fd37","version_start_inclusive":true,"version_end":"585cb85e9a29185be05f326369573c2663cf4380","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:288f30435132d2f9e7a29ec9b9745a4f9dc7fd37:585cb85e9a29185be05f326369573c2663cf4380"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"288f30435132d2f9e7a29ec9b9745a4f9dc7fd37","version_start_inclusive":true,"version_end":"7f2fcff15e99bb852f6967396ed12b38376e2c8d","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:288f30435132d2f9e7a29ec9b9745a4f9dc7fd37:7f2fcff15e99bb852f6967396ed12b38376e2c8d"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"6.17","version_start_inclusive":true,"version_end":"6.17","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:6.17:6.17"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"0","version_start_inclusive":true,"version_end":"6.17","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:0:6.17"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"6.18.36","version_start_inclusive":true,"version_end":"6.18.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:6.18.36:6.18.*"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"7.0.13","version_start_inclusive":true,"version_end":"7.0.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:7.0.13:7.0.*"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"7.1","version_start_inclusive":true,"version_end":"*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:7.1:*"}],"exploit_refs":[],"news":[],"references":[{"url":"https://git.kernel.org/stable/c/5fd1fa5a4254bfdd70571c77f5e3bcb4e43738d5","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/585cb85e9a29185be05f326369573c2663cf4380","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/7f2fcff15e99bb852f6967396ed12b38376e2c8d","source_type":"MISC","tags":[]}],"timeline":[{"type":"published","at":"2026-06-24T07:14:29.281000Z","label":"CVE published","source":null}]}