{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-99054", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.388Z", "datePublished": "2026-10-23T12:22:36.886Z", "dateUpdated": "2026-10-24T14:10:14.659Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-24T14:10:14.659Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: destroy topsrv workqueues before closing connections\n\ntipc_topsrv_stop() closed subscriber connections while the topology\nserver's send and receive workqueues were still running. Socket\ncallbacks and subscription events could then queue more work, and\nin-flight send/recv work could drop the last connection reference\nduring the conn_idr walk.\n\nThat race produced several teardown failures: refcount_t addition on\n0 from conn_get() on a connection whose release was blocked on\nidr_lock, a subsequent use-after-free in tipc_conn_close(),\nqueue_work() on an already destroyed workqueue from the listener\ndata-ready callback, and an RCU stall in tipc_topsrv_exit_net()\nwhile the walk spun under idr_lock.\n\nClear srv->listener under idr_lock so it acts as a shutdown flag,\nskip queue_work() once it is NULL, destroy the workqueues to flush\nin-flight work, and only then close the remaining connections.\nRefuse tipc_conn_lookup() after that flag is cleared, and drop\nidr_lock when the teardown walk finds no connection, so an\nin-flight subscription event cannot pin idr_in_use while the\nwalk holds the lock.\n\nv3 supersedes the narrower in-thread diff Tung Quang Nguyen\nposted on 2026-09-23. It keeps his teardown order and adds the\nlookup refusal and the empty-idr unlock." } ], "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 - `unshare(CLONE_NEWUSER|CLONE_NEWNET)` creates the per-net TIPC server; local `socket(AF_TIPC)`, `connect(TIPC_TOP_SRV)`, and `send()` churn followed by exit drives `cleanup_net()` -> `tipc_topsrv_exit_net()` -> patched `tipc_topsrv_stop()`. No remote message can cause the required namespace teardown.\nAC:L - The attacker controls both sides of the race: worker threads repeatedly create and close topology subscriptions while their process exits the network namespace, racing `rwork`/`swork` and socket callbacks against `tipc_topsrv_stop()`. No victim or hardware state is required.\nPR:L - `tipc_sk_create()`, `tipc_connect()`, and `tipc_conn_rcv_sub()` have no capability or authentication gate; an ordinary user can obtain the `CAP_SYS_ADMIN` needed for `CLONE_NEWNET` inside a new user namespace. No init-namespace privilege is required.\nUI:N - The attacker creates the namespaces, opens and floods `TIPC_TOP_SRV` connections, closes them, and exits to start `cleanup_net()` without any victim action.\nS:U - The freed `tipc_conn` and workqueue objects belong to the host kernel, and exploitation of `tipc_topsrv_stop()` affects that same kernel authority without crossing a VM, IOMMU, or other security boundary.\nC:H - `tipc_conn_kref_release()` frees `con` while teardown retains its address; `tipc_conn_close()` then reads `con->sock->sk` and follows reclaimed subscription and socket pointers. Reclaiming this object permits attacker-controlled pointer dereferences usable as kernel-memory read primitives.\nI:H - After the free, `tipc_conn_close()` modifies reclaimed `con->flags`, writes through `sk->sk_user_data`, processes reclaimed subscription lists, and calls `kernel_sock_shutdown()` through `con->sock->ops`. These provide memory-write and control-flow primitives.\nA:H - The reported race produced a page fault in `tipc_conn_close()`, `queue_work()` on a destroyed receive workqueue, and an RCU stall in `tipc_topsrv_exit_net()`; these paths can oops, panic, or wedge the system." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/tipc/topsrv.c" ], "versions": [ { "version": "c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f", "lessThan": "7f796bb3b440d7f1b14c0e3b520462eb34f553af", "status": "affected", "versionType": "git" }, { "version": "c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f", "lessThan": "da9c16568bc79140a54c1f5fcf07a0305df47b37", "status": "affected", "versionType": "git" }, { "version": "c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f", "lessThan": "0af8780bdfdfc91fb9127bddb9c48fab67dc9d9e", "status": "affected", "versionType": "git" }, { "version": "c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f", "lessThan": "fb717c536af2aafeca520ff11d1e0f25f7ab8fa9", "status": "affected", "versionType": "git" }, { "version": "c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f", "lessThan": "3acdd44385bc7e2e57605e073691ce69cc5a960d", "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/tipc/topsrv.c" ], "versions": [ { "version": "3.11", "status": "affected" }, { "version": "0", "lessThan": "3.11", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.113", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.11", "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": "3.11", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.11", "versionEndExcluding": "6.12.113" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.11", "versionEndExcluding": "6.18.57" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.11", "versionEndExcluding": "7.2.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.11", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/7f796bb3b440d7f1b14c0e3b520462eb34f553af" }, { "url": "https://git.kernel.org/stable/c/da9c16568bc79140a54c1f5fcf07a0305df47b37" }, { "url": "https://git.kernel.org/stable/c/0af8780bdfdfc91fb9127bddb9c48fab67dc9d9e" }, { "url": "https://git.kernel.org/stable/c/fb717c536af2aafeca520ff11d1e0f25f7ab8fa9" }, { "url": "https://git.kernel.org/stable/c/3acdd44385bc7e2e57605e073691ce69cc5a960d" } ], "title": "tipc: destroy topsrv workqueues before closing connections", "x_generator": { "engine": "bippy-1.2.0" } } } }