{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-64577", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-64577" ], "published": "2026-08-05T08:09:29Z", "summary": "gtp: check skb_pull_data() return in gtp1u_send_echo_resp()", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ngtp: check skb_pull_data() return in gtp1u_send_echo_resp()\n\ngtp1u_send_echo_resp() ignores skb_pull_data()'s return value. Its\ncaller gtp1u_udp_encap_recv() only guarantees 16 bytes (udphdr +\ngtp1_header), but the pull requests 20 (gtp1_header_long + udphdr). For\na 16-19 byte echo request the pull fails and returns NULL without\nadvancing skb->data; execution continues, and the following skb_push()\nplus the IP header pushed by iptunnel_xmit() move skb->data below\nskb->head, tripping skb_under_panic().\n\nFix it by dropping the packet when skb_pull_data() fails.\n\n skbuff: skb_under_panic: ...\n kernel BUG at net/core/skbuff.c:214!\n Call Trace:\n skb_push (net/core/skbuff.c:2648)\n iptunnel_xmit (net/ipv4/ip_tunnel_core.c:82)\n gtp_encap_recv (drivers/net/gtp.c:701 drivers/net/gtp.c:808 drivers/net/gtp.c:920)\n udp_queue_rcv_one_skb (net/ipv4/udp.c:2388)\n ...\n Kernel panic - not syncing: Fatal exception in interrupt", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.183", "compiled_filter": false } } } }, { "package": { "ecosystem": "Raspberry Pi OS:13", "name": "linux" }, "versions": [ "1:6.18.39-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.18.39+rpt-rpi-2712", "binary_version": "1:6.18.39-1+rpt1" }, { "binary_name": "linux-image-6.18.39+rpt-rpi-v6", "binary_version": "1:6.18.39-1+rpt1" }, { "binary_name": "linux-image-6.18.39+rpt-rpi-v7", "binary_version": "1:6.18.39-1+rpt1" }, { "binary_name": "linux-image-6.18.39+rpt-rpi-v8", "binary_version": "1:6.18.39-1+rpt1" }, { "binary_name": "linux-image-6.18.39+rpt-rpi-v8-rt", "binary_version": "1:6.18.39-1+rpt1" } ] }, "database_specific": { "per_version": { "1:6.18.39-1+rpt1": { "linux_commit": "60ea684a8ace97bb0db1a16e20753bdd6ab371ff", "upstream_version": "6.18.39", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.18.42" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-64577" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/9033fe49926f0e7421fefee922dc086417e905cf" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/b3c733eaae7f362601c28ac1533d47a961cd3e1c" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/4fc7923871d176ce0e5fecf4a9b7bb915af790ed" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/961e9b1e33445f8e42859ecc020c9f60d8b69a8b" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/cf45d748e437b8dd2dd987f27ee79c8c86f95c88" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/cd170f051dba9ac146fabcd1b91726487c0cb9fa" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-19T16:47:12Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.5, "cvss_v3_severity": "High", "scenario": "AV:N - A crafted GTP-U Echo Request to UDP port 2152 reaches gtp_encap_recv \u2192 gtp1u_udp_encap_recv \u2192 gtp1u_send_echo_resp via the in-kernel UDP encap receive path, so a remote IP peer can trigger the bug without local access.\nAC:L - The attacker fully controls the packet: a 16\u201319 byte GTP-U Echo Request with the S flag set and TEID 0 reliably fails the unchecked 20-byte pull and drives the subsequent skb_push path into skb_under_panic with no race or external condition required.\nPR:N - GTP-U echo handling runs on unauthenticated received UDP datagrams once a GTP device with kernel-created sockets exists; the attacker needs no credentials or local privileges on the target.\nUI:N - No victim action is required; packet delivery to the GTP-U encap socket alone invokes the vulnerable echo-response path.\nS:U - Impact is a kernel BUG/panic in the host GTP/network stack within the same security authority; it does not cross a VM, IOMMU, or other separate boundary.\nC:N - The failure is a deterministic skb headroom underflow caught by skb_under_panic/BUG with no out-of-bounds read, UAF, or other information-disclosure primitive identified.\nI:N - skb_push detects data < head and BUG()s before further attacker-controlled writes; this is an availability crash, not an exploitable write or control-flow hijack primitive.\nA:H - The commit-reproduced path hits skb_under_panic and a fatal kernel BUG in interrupt context, causing kernel panic and full denial of service that can be retriggered by further crafted echo requests." } } }