{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-98401", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-98401", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-10-14T13:26:01.712Z", "updatedAt": "2026-10-19T09:18:54.736Z", "importedAt": "2026-10-24T01:58:41.756Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "net: iptunnel: fix stale transport header during tunnel decapsulation", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: iptunnel: fix stale transport header during tunnel decapsulation\n\nSyzbot reported a crash in qdisc_pkt_len_segs_init() caused by a stale\ntransport_header offset after tunnel decapsulation.\n\nBUG: unable to handle page fault for address: ffffed102091a42e\nOops: Oops: 0000 [#1] SMP KASAN NOPTI\nCPU: 0 UID: 0 PID: 340 Comm: qdisc_uaf_repro Not tainted 7.2.0-rc4-00061-g248951ddc14d #256 PREEMPT(full)\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nRIP: 0010:__asan_load2\n\nqdisc_pkt_len_segs_init (net/core/dev.c:4145)\n__dev_queue_xmit (net/core/dev.c:4787)\nbr_dev_queue_push_xmit (net/bridge/br_forward.c:53)\nbr_handle_frame_finish (net/bridge/br_input.c:229)\nbr_handle_frame (net/bridge/br_input.c:315)\n__netif_receive_skb_core.constprop.0 (net/core/dev.c:6099)\n__netif_receive_skb_list_core (net/core/dev.c:6287)\nnetif_receive_skb_list_internal (net/core/dev.c:6445)\nnapi_complete_done (net/core/dev.c:6813)\ngro_cell_poll (net/core/gro_cells.c:74)\n__napi_poll (net/core/dev.c:7735)\nnet_rx_action (net/core/dev.c:7798 net/core/dev.c:7955)\nhandle_softirqs (kernel/softirq.c:622)\ndo_softirq (kernel/softirq.c:523 kernel/softirq.c:510 )\n__local_bh_enable_ip (kernel/softirq.c:450)\ntun_get_user (drivers/net/tun.c:1986 (discriminator 1))\ntun_chr_write_iter (drivers/net/tun.c:2032)\n\nThe issue is completely latent until qdisc read transport header in\ncommit 7fb4c1967011 (\"net: pull headers in qdisc_pkt_len_segs_init()\").\nThe crash requires four conditions to line up:\n\n1. The incoming packet is encapsulated and carries GSO metadata. The outer\n transport header offset is stored in skb->transport_header while the\n packet is still in the outer tunnel context.\n2. The tunnel receiver strips the outer headers. skb->data is advanced to\n the inner frame, but skb->transport_header is left pointing to the\n now-removed outer L4 header, so it becomes a negative offset relative to\n the new data.\n3. The inner frame is not delivered to the local IP stack. Instead, it\n is forwarded at L2 by a bridge or HSR, so ip_rcv_core() never runs and\n the transport header is not reset to the inner L4 offset.\n4. The forwarding path calls __dev_queue_xmit(), which enters\n qdisc_pkt_len_segs_init(). That function computes the GSO header length\n from skb_transport_offset(skb). Because the offset is negative, the\n unsigned cast overflows and pskb_may_pull(skb, hdr_len +\n sizeof(struct tcphdr)) reads past the end of the skb, triggering a\n KASAN fault or page fault.\n\nThe issue specifically requires GSO packets (shinfo->gso_size != 0), which\nare processed/aggregated through gro_cells. Fix this by clearing\ntransport_header to the ~0U sentinel in gro_cell for all tunnnel driver.\nGTP does not support GRO/GSO, drop the evil GSO packets in GTP directly.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "8c3d4dfcecf7670c1d752f1ae74b21b2af5feac1" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "e4a5b01e59f7102169762b8f566c8e052d05c0ff" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "3340b8565b85631cfeb0df049e8b46e3ef8bd7bd" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "28a57fb2c5df4deb42a06e52fd36c14b37aa0034" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "2.6.12" }, { "version": "6.12.111", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.53", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.2.7", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.2.*" }, { "version": "7.3", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }