{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-23450 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-23450 is a critical use after free vulnerability in Linux kernel, published on 3 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-23450 and fix it if it is affected.\n\nWhat it is: CVE-2026-23450 is a critical use after free vulnerability in Linux kernel, published on 3 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-23450 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-23450/ (Markdown: https://insights.sbomify.com/CVE-2026-23450/index.md)","id":"CVE-2026-23450","markdown":"https://insights.sbomify.com/CVE-2026-23450/index.md","name":"CVE-2026-23450","record":{"aliases":["BELL-CVE-2026-23450","DEBIAN-CVE-2026-23450","GHSA-m7g4-hqc4-25c8","ROOT-OS-DEBIAN-12-CVE-2026-23450","ROOT-OS-DEBIAN-13-CVE-2026-23450","ROOT-OS-UBUNTU-2204-CVE-2026-23450","ROOT-OS-UBUNTU-2404-CVE-2026-23450","UBUNTU-CVE-2026-23450"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel SMC","requires_auth":"none","summary":"A race condition in the Linux kernel SMC module allows a local attacker to trigger a use-after-free or NULL dereference, causing a system crash.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":9.8,"severity":"critical","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-416","name":"Use After Free"},{"id":"CWE-362","name":"Concurrent Execution using Shared Resource with Improper Synchronization"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix NULL dereference and UAF in smc_tcp_syn_recv_sock()\n\nSyzkaller reported a panic in smc_tcp_syn_recv_sock() [1].\n\nsmc_tcp_syn_recv_sock() is called in the TCP receive path\n(softirq) via icsk_af_ops-\u003esyn_recv_sock on the clcsock (TCP\nlistening socket). It reads sk_user_data to get the smc_sock\npointer. However, when the SMC listen socket is being closed\nconcurrently, smc_close_active() sets clcsock-\u003esk_user_data\nto NULL under sk_callback_lock, and then the smc_sock itself\ncan be freed via sock_put() in smc_release().\n\nThis leads to two issues:\n\n1) NULL pointer dereference: sk_user_data is NULL when\n   accessed.\n2) Use-after-free: sk_user_data is read as non-NULL, but the\n   smc_sock is freed before its fields (e.g., queued_smc_hs,\n   ori_af_ops) are accessed.\n\nThe race window looks like this (the syzkaller crash [1]\ntriggers via the SYN cookie path: tcp_get_cookie_sock() -\u003e\nsmc_tcp_syn_recv_sock(), but the normal tcp_check_req() path\nhas the same race):\n\n  CPU A (softirq)              CPU B (process ctx)\n\n  tcp_v4_rcv()\n    TCP_NEW_SYN_RECV:\n    sk = req-\u003ersk_listener\n    sock_hold(sk)\n    /* No lock on listener */\n                               smc_close_active():\n                                 write_lock_bh(cb_lock)\n                                 sk_user_data = NULL\n                                 write_unlock_bh(cb_lock)\n                                 ...\n                                 smc_clcsock_release()\n                                 sock_put(smc-\u003esk) x2\n                                   -\u003e smc_sock freed!\n    tcp_check_req()\n      smc_tcp_syn_recv_sock():\n        smc = user_data(sk)\n          -\u003e NULL or dangling\n        smc-\u003equeued_smc_hs\n          -\u003e crash!\n\nNote that the clcsock and smc_sock are two independent objects\nwith separate refcounts. TCP stack holds a reference on the\nclcsock, which keeps it alive, but this does NOT prevent the\nsmc_sock from being freed.\n\nFix this by using RCU and refcount_inc_not_zero() to safely\naccess smc_sock. Since smc_tcp_syn_recv_sock() is called in\nthe TCP three-way handshake path, taking read_lock_bh on\nsk_callback_lock is too heavy and would not survive a SYN\nflood attack. Using rcu_read_lock() is much more lightweight.\n\n- Set SOCK_RCU_FREE on the SMC listen socket so that\n  smc_sock freeing is deferred until after the RCU grace\n  period. This guarantees the memory is still valid when\n  accessed inside rcu_read_lock().\n- Use rcu_read_lock() to protect reading sk_user_data.\n- Use refcount_inc_not_zero(\u0026smc-\u003esk.sk_refcnt) to pin the\n  smc_sock. If the refcount has already reached zero (close\n  path completed), it returns false and we bail out safely.\n\nNote: smc_hs_congested() has a similar lockless read of\nsk_user_data without rcu_read_lock(), but it only checks for\nNULL and accesses the global smc_hs_wq, never dereferencing\nany smc_sock field, so it is not affected.\n\nReproducer was verified with mdelay injection and smc_run,\nthe issue no longer occurs with this patch applied.\n\n[1] https://syzkaller.appspot.com/bug?extid=827ae2bfb3a3529333e9","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"net/smc: fix NULL dereference and UAF in smc_tcp_syn_recv_sock()","id":"CVE-2026-23450","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"use_after_free","year":"2026"},"n_packages":0,"n_references":7,"next":{"headline":"bonding: prevent potential infinite loop in bond_header_parse()","id":"CVE-2026-23451"},"packages":[],"prev":{"headline":"net/sched: teql: Fix double-free in teql_master_xmit","id":"CVE-2026-23449"},"products":["Linux"],"published":"2026-04-03","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-10-19","vendors":["Linux"]},"summary":"A race condition in the Linux kernel SMC module allows a local attacker to trigger a use-after-free or NULL dereference, causing a system crash.","url":"https://insights.sbomify.com/CVE-2026-23450/"}