{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-63801", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-63801" ], "published": "2026-07-19T12:02:32Z", "summary": "tipc: fix slab-use-after-free Read in tipc_aead_decrypt_done", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: fix slab-use-after-free Read in tipc_aead_decrypt_done\n\ntipc_aead_decrypt() goes straight from tipc_bearer_hold(b) to\ncrypto_aead_decrypt(req) without taking a reference on the netns, unlike\nthe encrypt path. When crypto_aead_decrypt() is offloaded asynchronously\n(e.g. the SIMD aead wrapper queuing to cryptd), the cryptd worker runs\ntipc_aead_decrypt_done() later. If the bearer's netns is torn down in the\nmeantime, cleanup_net() -> tipc_exit_net() -> tipc_crypto_stop() frees the\nper-netns tipc_crypto, and the completion then reads it:\ntipc_aead_decrypt_done() dereferences aead->crypto->stats and\naead->crypto->net, and tipc_crypto_rcv_complete() dereferences\naead->crypto->aead[] and the node table -- reading freed memory.\n\nDecoded KASAN splat (v7.1-rc7, CONFIG_KASAN_INLINE + TIPC + TIPC_CRYPTO):\n\n BUG: KASAN: slab-use-after-free in tipc_aead_decrypt_done (net/tipc/crypto.c:999)\n Read of size 8 at addr ffff8881056258a8 by task kworker/u16:2/51\n Workqueue: events_unbound\n Call Trace:\n tipc_aead_decrypt_done (net/tipc/crypto.c:999)\n process_one_work (kernel/workqueue.c:3314)\n worker_thread (kernel/workqueue.c:3397 kernel/workqueue.c:3478)\n kthread (kernel/kthread.c:436)\n ret_from_fork (arch/x86/kernel/process.c:158)\n ret_from_fork_asm (arch/x86/entry/entry_64.S:245)\n\n Allocated by task 169:\n __kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415)\n tipc_crypto_start (net/tipc/crypto.c:1502)\n tipc_init_net (net/tipc/core.c:72)\n ops_init (net/core/net_namespace.c:137)\n setup_net (net/core/net_namespace.c:446)\n copy_net_ns (net/core/net_namespace.c:579)\n create_new_namespaces (kernel/nsproxy.c:132)\n __x64_sys_unshare (kernel/fork.c:3316)\n do_syscall_64 (arch/x86/entry/syscall_64.c:63)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n\n Freed by task 8:\n kfree (mm/slub.c:6566)\n tipc_exit_net (net/tipc/core.c:119)\n cleanup_net (net/core/net_namespace.c:704)\n process_one_work (kernel/workqueue.c:3314)\n kthread (kernel/kthread.c:436)\n\nThis is the same class of bug that commit e279024617134 (\"net/tipc: fix\nslab-use-after-free Read in tipc_aead_encrypt_done\") fixed for the encrypt\nside. The encrypt path takes maybe_get_net(aead->crypto->net) before\ncrypto_aead_encrypt() and drops it with put_net() on the synchronous\nreturn paths and in tipc_aead_encrypt_done(); the -EINPROGRESS/-EBUSY\nreturn keeps the reference for the async callback to release. The decrypt\npath was left without the equivalent guard.\n\nMirror the encrypt-side fix on the decrypt path: take a net reference\nbefore crypto_aead_decrypt() (failing with -ENODEV and the matching\nbearer put if it cannot be acquired), keep it across the\n-EINPROGRESS/-EBUSY async return, and drop it with put_net() on the\nsynchronous success/error return and at the end of\ntipc_aead_decrypt_done().\n\nReproduced under KASAN on v7.1-rc7: a UDP bearer with a cluster key is\nflooded with crafted encrypted frames from an unknown peer (driving the\ncluster-key decrypt path) while the bearer's netns is repeatedly torn\ndown. The completion must run asynchronously to outlive\ntipc_crypto_stop(); on x86 the stock aesni gcm(aes) now decrypts\nsynchronously, so the async path was exercised via cryptd offload. The\nunguarded aead->crypto dereference in tipc_aead_decrypt_done() is the\nunpatched upstream path; tipc_aead_decrypt() still lacks\nmaybe_get_net(aead->crypto->net), so the completion can outlive the free\non any config where crypto_aead_decrypt() goes async.\n\nFound by 0sec automated security-research tooling (https://0sec.ai).", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.177", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-63801" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/171d31245d11bf84836fad3b394cb465a4d008ec" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/2d1f21419ec121232c916d3a3fc9b6766473a0e7" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/0a780653b2a7569a7af9be7d0b00b1251baca63a" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/eaca7dae02fab70c8d223cffe03cec1b93249ce2" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/dca7713fe044a2067387948557ea099056e1679e" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/e18769616fd5a90ec1e12aabbba544c488284292" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/1eea5e1820a2f5164d706bd1277bc97ff31ce32d" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/bda3348872a2ef0d19f2df6aa8cb5025adce2f20" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-17T05:24:08Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 8.8, "cvss_v3_severity": "High", "scenario": "AV:N - The vulnerable code is reached from the TIPC packet receive path (UDP bearer on port 6118 or L2 bearer) when encrypted frames arrive from a remote peer; no local syscall is required to enter tipc_aead_decrypt().\nAC:L - The attacker can reliably win the race by flooding packets to queue async decrypt completions while repeatedly destroying the network namespace; the repro demonstrates full control of both sides of the timing window.\nPR:L - Reliable exploitation is demonstrated via unshare-created user/network namespaces where the attacker gains CAP_NET_ADMIN-equivalent control to configure TIPC crypto and cycle namespace teardown, which per kernel CNA guidance maps to Low rather than High.\nUI:N - Exploitation requires only sending network packets and namespace lifecycle manipulation; no victim user action such as opening a file or mounting a filesystem is needed.\nS:U - Impact is confined to kernel memory within the same security authority; this is a standard kernel UAF/privilege-escalation class bug, not a VM escape or cross-authority boundary bypass.\nC:H - The UAF reads freed slab memory including aead->crypto->stats, aead->crypto->net, and aead[] pointers in tipc_crypto_rcv_complete, enabling arbitrary kernel memory disclosure via controlled reuse of the freed tipc_crypto object.\nI:H - Use-after-free of tipc_crypto structures can be leveraged for heap spraying and arbitrary write primitives, and tipc_crypto_rcv_complete continues processing with freed pointers including key attachment and node table operations.\nA:H - KASAN confirmed slab-use-after-free in tipc_aead_decrypt_done on a workqueue thread; UAF on this path causes kernel oops/panic even when not fully exploited for code execution." } } }