{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89789", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.766Z", "datePublished": "2026-09-16T08:48:25.689Z", "dateUpdated": "2026-10-19T08:52:43.083Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:52:43.083Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngtp: add synchronize_net() in gtp_newlink() error path to prevent use-after-free\n\ngtp_newlink()'s error path frees tid_hash and addr_hash without\nwaiting for an RCU grace period after clearing sk_user_data. A\nconcurrent gtp_encap_recv() in softirq may still hold the gtp_dev\npointer obtained via rcu_dereference_sk_user_data() and access the\nfreed memory.\n\n BUG: KASAN: slab-use-after-free in gtp0_pdp_find+0x1f6/0x200 (gtp.c:152)\n Call Trace:\n \n gtp0_pdp_find+0x1f6/0x200\n gtp_encap_recv+0x527/0x24b0\n udp_queue_rcv_one_skb+0x75f/0xc10\n\nAdd synchronize_net() before the kfree calls in out_hashtable, which\ncovers all error paths from both gtp_encap_enable() and\ngtp_create_sockets()." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The UAF is triggered from gtp_newlink()'s RTM_NEWLINK error path (ip link add type gtp), a local rtnetlink configuration interface. Concurrent gtp_encap_recv() in softirq only uses already-freed tid_hash/addr_hash; a remote GTP-U peer cannot cause the free.\nAC:L - The attacker controls both sides of the RCU race: one thread issues RTM_NEWLINK that fails after setup_udp_tunnel_sock() (invalid second FD, IPv4/IPv6 family mismatch, or register_netdevice failure) while another floods UDP datagrams at the encap socket so gtp_encap_recv() still holds the gtp_dev pointer across the kfree.\nPR:L - Creating a GTP device requires CAP_NET_ADMIN in the target netns via rtnl_link_get_net_capable()/netlink_ns_capable(). Unprivileged users obtain this through user+network namespaces (unshare -Urn); gtp_link_ops has no extra init-namespace check and MODULE_ALIAS_RTNL_LINK(\"gtp\") permits module autoload.\nUI:N - The attacker opens its own UDP sockets, sends packets to them, and issues the failing RTM_NEWLINK from its own process. No separate victim action such as mounting a filesystem or opening a file is required.\nS:U - Impact is a host-kernel slab use-after-free in drivers/net/gtp.c, i.e. standard local privilege escalation within the same kernel security authority, not a KVM/Xen guest-to-host escape or IOMMU/DMA boundary bypass.\nC:H - gtp0_pdp_find()/gtp1_pdp_find() walk the attacker-sized freed tid_hash hlist under RCU. Heap spraying that slab yields a fake pdp_ctx and an arbitrary kernel read primitive, so Confidentiality is High per UAF guidance.\nI:H - A sprayed fake pdp_ctx is passed to gtp_rx(), which writes device stats, assigns skb->dev, and calls __netif_rx(); combined with UAF heap reuse this is an arbitrary write and control-flow hijack primitive, so Integrity is High.\nA:H - KASAN reports slab-use-after-free in gtp0_pdp_find from gtp_encap_recv in softirq (udp_queue_rcv_one_skb). The UAF causes a kernel oops or panic even when not fully exploited, so Availability is High." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/gtp.c" ], "versions": [ { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "fcafb2b1430824bae4258c01a439ec97ca0c6973", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "3ca3da5c305caa873ddb81e8c6b118143f6dd3d1", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "6f815c2fb6ab20385f81c353cdad0ea3b88132af", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "e3b9aa0773abd5d4ed90be41ce5306c146d5b09e", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "fd8396cfecbd904468c71362f08aaa25f96d5337", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "7677eb2cbf2cc7446de474c01a6b06277c0051e5", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "8d85498016a5bb56339734a14c276209fa65bafc", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "d989e22ae9802c52c56ad4284d0caf26696cf6ae", "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/gtp.c" ], "versions": [ { "version": "4.7", "status": "affected" }, { "version": "0", "lessThan": "4.7", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.52", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.6", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "4.7", "versionEndExcluding": "5.10.270" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "5.15.221" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.12.110" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.18.52" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "7.2.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/fcafb2b1430824bae4258c01a439ec97ca0c6973" }, { "url": "https://git.kernel.org/stable/c/3ca3da5c305caa873ddb81e8c6b118143f6dd3d1" }, { "url": "https://git.kernel.org/stable/c/6f815c2fb6ab20385f81c353cdad0ea3b88132af" }, { "url": "https://git.kernel.org/stable/c/e3b9aa0773abd5d4ed90be41ce5306c146d5b09e" }, { "url": "https://git.kernel.org/stable/c/fd8396cfecbd904468c71362f08aaa25f96d5337" }, { "url": "https://git.kernel.org/stable/c/7677eb2cbf2cc7446de474c01a6b06277c0051e5" }, { "url": "https://git.kernel.org/stable/c/8d85498016a5bb56339734a14c276209fa65bafc" }, { "url": "https://git.kernel.org/stable/c/d989e22ae9802c52c56ad4284d0caf26696cf6ae" } ], "title": "gtp: add synchronize_net() in gtp_newlink() error path to prevent use-after-free", "x_generator": { "engine": "bippy-1.2.0" } } } }