{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72408", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.926Z", "datePublished": "2026-08-15T05:56:31.477Z", "dateUpdated": "2026-08-17T05:43:48.541Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:43:48.541Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngeneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint\n\ngeneve_gro_receive() reads the GRO hint through geneve_sk_gro_hint_off(),\nwhich honours it only when the socket enabled IFLA_GENEVE_GRO_HINT\n(gs->gro_hint). geneve_gro_complete() instead calls the low-level\ngeneve_opt_gro_hint_off() and acts on the hint unconditionally.\n\nOn a tunnel without the hint, receive aggregates the frames as plain\nETH_P_TEB while complete still honours an attacker-supplied hint option: it\ninflates gh_len by gro_hint->nested_hdr_len (u8) and redirects the dispatch\ntype, so the inner gro_complete handler runs at nhoff + gh_len, an offset\nreceive never pulled nor validated, reading out of bounds of the skb head:\n\n BUG: KASAN: slab-out-of-bounds in ipv6_gro_complete (net/ipv6/ip6_offload.c:196)\n Read of size 1 at addr ffff88800fe91980 by task exploit/153\n ipv6_gro_complete (net/ipv6/ip6_offload.c:196)\n geneve_gro_complete (drivers/net/geneve.c:965)\n udp_gro_complete (net/ipv4/udp_offload.c:940)\n inet_gro_complete (net/ipv4/af_inet.c:1621)\n __gro_flush (net/core/gro.c:306)\n\nGate the complete path on gs->gro_hint too via geneve_sk_gro_hint_off(), so\nboth paths agree. Tunnels that enable the hint are unaffected." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H", "baseScore": 10, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The bug is triggered by remotely delivered UDP/GENEVE packets processed in the NAPI GRO completion path (udp_gro_complete → geneve_gro_complete → __gro_flush), not via local syscalls or physical interfaces.\nAC:L - The attacker controls all packet fields (GRO hint option, nested_hdr_len, inner_proto_id) and can send multiple matching datagrams to force GRO aggregation/flush; no uncontrollable race or memory layout is required.\nPR:N - No authentication or local privileges are needed; any remote host that can send UDP to a victim's GENEVE tunnel port triggers the flaw on default tunnels without IFLA_GENEVE_GRO_HINT enabled.\nUI:N - Exploitation requires only transmission of crafted network packets; no victim interaction such as opening files, mounting filesystems, or clicking links is needed.\nS:C - In cloud/Kubernetes overlay deployments using GENEVE, a malicious tenant VM or pod can attack the host/hypervisor kernel over the underlay network, crossing the tenant-to-host security boundary.\nC:H - geneve_gro_complete() honors attacker-supplied GRO hint options that gro_receive() ignored, inflating gh_len and dispatching inner gro_complete past validated skb data, causing slab out-of-bounds reads and enabling arbitrary kernel memory disclosure.\nI:H - Misdirected gro_complete handlers (e.g., ipv6_gro_complete) read and rewrite protocol header fields at attacker-chosen offsets beyond the skb head, providing out-of-bounds write primitives exploitable for control-flow hijacking.\nA:H - The vulnerability provokes KASAN slab-out-of-bounds faults and kernel oops during GRO flush; repeated remote triggering can panic or hang the host, denying availability to all workloads." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/geneve.c" ], "versions": [ { "version": "fd0dd796576e1a560e1441e665810129f0a82be0", "lessThan": "49c2e7c0a69999a75ef5eaebe1559a20d0b3c15a", "status": "affected", "versionType": "git" }, { "version": "fd0dd796576e1a560e1441e665810129f0a82be0", "lessThan": "2651c174445884ac9e85622aeade9c1f7b98d8e5", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/geneve.c" ], "versions": [ { "version": "7.0", "status": "affected" }, { "version": "0", "lessThan": "7.0", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/49c2e7c0a69999a75ef5eaebe1559a20d0b3c15a" }, { "url": "https://git.kernel.org/stable/c/2651c174445884ac9e85622aeade9c1f7b98d8e5" } ], "title": "geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint", "x_generator": { "engine": "bippy-1.2.0" } } } }