{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40133", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.170Z", "datePublished": "2025-11-12T10:23:22.498Z", "dateUpdated": "2026-08-05T12:07:59.353Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:07:59.353Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable().\n\nmptcp_active_enable() is called from subflow_finish_connect(),\nwhich is icsk->icsk_af_ops->sk_rx_dst_set() and it's not always\nunder RCU.\n\nUsing sk_dst_get(sk)->dev could trigger UAF.\n\nLet's use __sk_dst_get() and dst_dev_rcu()." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The stale `dst->dev` dereference executes while processing a remote peer's SYN-ACK — `tcp_finish_connect()` → `icsk_af_ops->sk_rx_dst_set()` → `subflow_finish_connect()` → `mptcp_active_enable()` — so remote network data drives entry into the vulnerable code, and the peer also controls the MP_CAPABLE/blackhole state that unlocks the guarded block. Any MPTCP-enabled host making outbound connections (mobile/carrier stacks, mptcpize'd services, MPTCP proxies) is exposed to a malicious or on-path server.\nAC:H - The attacker controls one side of the race (when the SYN-ACK arrives and thus when `dst->dev` is read), but the other side requires the route's `net_device` to be concurrently unregistered so `dst_dev_put()`/`netdev_ref_replace()` drops the last reference and `free_netdev()` runs — a local netdev-teardown event a remote peer can neither induce nor time, as is landing the SYN-ACK in the socket backlog (non-RCU process context) rather than softirq.\nPR:N - The vulnerable code runs during the TCP/MPTCP handshake itself, before any application-level authentication or credential exchange, so the remote peer needs no privileges or account of any kind on the target.\nUI:N - Outbound MPTCP connections are made automatically by daemons, mobile connectivity stacks, and proxies without any human action, and an on-path attacker can simply inject the MP_CAPABLE SYN-ACK for a connection the host initiates on its own.\nS:U - The use-after-free is on a kernel `struct net_device` and its effects stay within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - This is a use-after-free read of a freed, heap-sprayable `net_device`, and a reclaimed slab can be groomed with attacker-influenced data, giving a read primitive over reclaimed kernel memory; the value read (`dev->flags & IFF_LOOPBACK`) further acts as an oracle since it determines whether `active_disable_times` is cleared, which is observable through subsequent MPTCP fallback behaviour and the MPTCP MIB counters.\nI:H - A use-after-free on a `net_device` is a heap-corruption primitive whose reclaimed contents are attacker-influenceable via spraying, and here freed memory directly steers a kernel state write (`atomic_set(&pernet->active_disable_times, 0)`), letting uncontrolled reclaimed data modify per-namespace MPTCP protocol state and, once the slab is groomed, be escalated toward arbitrary write and control-flow hijack.\nA:H - Dereferencing a freed `net_device` — allocated with `kvzalloc` and potentially unmapped on free — reliably produces a kernel oops or panic even when not weaponized, and the trigger can be retried indefinitely for a persistent denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/mptcp/ctrl.c" ], "versions": [ { "version": "27069e7cb3d1cea9377069266acf19b9cc5ad0ae", "lessThan": "ad16235c9d3ef7ec17c109ff39b7504f49d17072", "status": "affected", "versionType": "git" }, { "version": "27069e7cb3d1cea9377069266acf19b9cc5ad0ae", "lessThan": "cc976ec9e38bb79409de3261ba1dbb6868e2a53e", "status": "affected", "versionType": "git" }, { "version": "27069e7cb3d1cea9377069266acf19b9cc5ad0ae", "lessThan": "893c49a78d9f85e4b8081b908fb7c407d018106a", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/mptcp/ctrl.c" ], "versions": [ { "version": "6.12", "status": "affected" }, { "version": "0", "lessThan": "6.12", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.55", "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": "6.12", "versionEndExcluding": "6.12.55" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "6.17.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/ad16235c9d3ef7ec17c109ff39b7504f49d17072" }, { "url": "https://git.kernel.org/stable/c/cc976ec9e38bb79409de3261ba1dbb6868e2a53e" }, { "url": "https://git.kernel.org/stable/c/893c49a78d9f85e4b8081b908fb7c407d018106a" } ], "title": "mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable().", "x_generator": { "engine": "bippy-1.2.0" } } } }