{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40170", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.176Z", "datePublished": "2025-11-12T10:46:52.014Z", "dateUpdated": "2026-08-05T12:08:15.716Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:08:15.716Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: use dst_dev_rcu() in sk_setup_caps()\n\nUse RCU to protect accesses to dst->dev from sk_setup_caps()\nand sk_dst_gso_max_size().\n\nAlso use dst_dev_rcu() in ip6_dst_mtu_maybe_forward(),\nand ip_dst_mtu_maybe_forward().\n\nip4_dst_hoplimit() can use dst_dev_net_rcu()." } ], "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 unprotected `sk_setup_caps()` reader is reached from process-context syscalls (connect/sendmsg/SCTP output), and the racing `dst_dev_put()`/netdev-unregister side requires local netns and link/route manipulation; the remote-triggered call site (`tcp_v4_syn_recv_sock`) runs BH-disabled and is implicitly RCU-protected.\nAC:L - The attacker controls both sides of the race — one thread loops connect()/sendmsg() on sockets holding the dst while another deletes the veth/route in its own netns — and can retry indefinitely until the window is hit.\nPR:L - An unprivileged local account suffices; CAP_NET_ADMIN needed for link/route teardown is obtainable without real root via user namespaces (`unshare -Urn`), and the socket side needs no privilege at all.\nUI:N - Exploitation is entirely driven by the attacker's own threads issuing socket syscalls and netlink link/route operations; no victim action is required.\nS:U - The use-after-free is on a kernel `struct net_device` and its effects stay within the kernel's own security authority, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - This is a use-after-free read of a freed, heap-sprayable `net_device`; its contents are loaded into `sk_route_caps`, `sk_gso_max_size` and `sk_gso_max_segs`, which observably alter TCP segmentation and thus leak freed-memory contents, and per UAF guidance this is High.\nI:H - Values read from freed memory are written into persistent socket state and then drive packet construction — bogus SG/HW_CSUM/GSO feature bits and an underflowed multi-gigabyte `sk_gso_max_size` corrupt the TX path, and a UAF on a sprayable object is treatable as an arbitrary-write primitive.\nA:H - Dereferencing a freed `net_device` can oops outright, and the resulting garbage GSO sizes/segment counts produce oversized skb allocations and inconsistent offload state that crash the transmit path and drivers." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/ip.h", "include/net/ip6_route.h", "include/net/route.h", "net/core/sock.c" ], "versions": [ { "version": "4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36", "lessThan": "5d1be493d1110c9e720b4c51a6e587bb2fb4ac12", "status": "affected", "versionType": "git" }, { "version": "4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36", "lessThan": "a805729c0091073d8f0415cfa96c7acd1bc17a48", "status": "affected", "versionType": "git" }, { "version": "4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36", "lessThan": "99a2ace61b211b0be861b07fbaa062fca4b58879", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/ip.h", "include/net/ip6_route.h", "include/net/route.h", "net/core/sock.c" ], "versions": [ { "version": "4.13", "status": "affected" }, { "version": "0", "lessThan": "4.13", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.64", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.3", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "4.13", "versionEndExcluding": "6.12.64" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.17.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5d1be493d1110c9e720b4c51a6e587bb2fb4ac12" }, { "url": "https://git.kernel.org/stable/c/a805729c0091073d8f0415cfa96c7acd1bc17a48" }, { "url": "https://git.kernel.org/stable/c/99a2ace61b211b0be861b07fbaa062fca4b58879" } ], "title": "net: use dst_dev_rcu() in sk_setup_caps()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-06-16T19:33:10.426175Z", "id": "CVE-2025-40170", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-16T19:33:20.303Z" } } ] } }