{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-45866 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-45866 is a high-severity use after free vulnerability in Linux kernel, published on 27 May 2026. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-45866 and fix it if it is affected.\n\nWhat it is: CVE-2026-45866 is a high-severity use after free vulnerability in Linux kernel, published on 27 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-45866 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-2026-45866/ (Markdown: https://insights.sbomify.com/CVE-2026-45866/index.md)","id":"CVE-2026-45866","markdown":"https://insights.sbomify.com/CVE-2026-45866/index.md","name":"CVE-2026-45866","record":{"aliases":["BELL-CVE-2026-45866","DEBIAN-CVE-2026-45866","GHSA-9834-966g-q77h","ROOT-OS-DEBIAN-11-CVE-2026-45866","ROOT-OS-UBUNTU-2204-CVE-2026-45866","ROOT-OS-UBUNTU-2404-CVE-2026-45866","UBUNTU-CVE-2026-45866"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","privilege_escalation"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A use-after-free vulnerability in the Linux kernel's CAIF serial driver allows attackers to execute arbitrary code or escalate privileges via a race condition.","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":7.8,"severity":"high","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-416","name":"Use After Free"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nserial: caif: fix use-after-free in caif_serial ldisc_close()\n\nThere is a use-after-free bug in caif_serial where handle_tx() may\naccess ser-\u003etty after the tty has been freed.\n\nThe race condition occurs between ldisc_close() and packet transmission:\n\n    CPU 0 (close)                     CPU 1 (xmit)\n    -------------                     ------------\n    ldisc_close()\n      tty_kref_put(ser-\u003etty)\n      [tty may be freed here]\n                     \u003c-- race window --\u003e\n                                      caif_xmit()\n                                        handle_tx()\n                                          tty = ser-\u003etty  // dangling ptr\n                                          tty-\u003eops-\u003ewrite() // UAF!\n      schedule_work()\n        ser_release()\n          unregister_netdevice()\n\nThe root cause is that tty_kref_put() is called in ldisc_close() while\nthe network device is still active and can receive packets.\n\nSince ser and tty have a 1:1 binding relationship with consistent\nlifecycles (ser is allocated in ldisc_open and freed in ser_release\nvia unregister_netdevice, and each ser binds exactly one tty), we can\nsafely defer the tty reference release to ser_release() where the\nnetwork device is unregistered.\n\nFix this by moving tty_kref_put() from ldisc_close() to ser_release(),\nafter unregister_netdevice(). This ensures the tty reference is held\nas long as the network device exists, preventing the UAF.\n\nNote: We save ser-\u003etty before unregister_netdevice() because ser is\nembedded in netdev's private data and will be freed along with netdev\n(needs_free_netdev = true).\n\nHow to reproduce: Add mdelay(500) at the beginning of ldisc_close()\nto widen the race window, then run the reproducer program [1].\n\nNote: There is a separate deadloop issue in handle_tx() when using\nPORT_UNKNOWN serial ports (e.g., /dev/ttyS3 in QEMU without proper\nserial backend). This deadloop exists even without this patch,\nand is likely caused by inconsistency between uart_write_room() and\nuart_write() in serial core. It has been addressed in a separate\npatch [2].\n\nKASAN report:\n\n==================================================================\nBUG: KASAN: slab-use-after-free in handle_tx+0x5d1/0x620\nRead of size 1 at addr ffff8881131e1490 by task caif_uaf_trigge/9929\n\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x10e/0x1f0\n print_report+0xd0/0x630\n kasan_report+0xe4/0x120\n handle_tx+0x5d1/0x620\n dev_hard_start_xmit+0x9d/0x6c0\n __dev_queue_xmit+0x6e2/0x4410\n packet_xmit+0x243/0x360\n packet_sendmsg+0x26cf/0x5500\n __sys_sendto+0x4a3/0x520\n __x64_sys_sendto+0xe0/0x1c0\n do_syscall_64+0xc9/0xf80\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7f615df2c0d7\n\nAllocated by task 9930:\n\nFreed by task 64:\n\nLast potentially related work creation:\n\nThe buggy address belongs to the object at ffff8881131e1000\n which belongs to the cache kmalloc-cg-2k of size 2048\nThe buggy address is located 1168 bytes inside of\n freed 2048-byte region [ffff8881131e1000, ffff8881131e1800)\n\nThe buggy address belongs to the physical page:\npage_owner tracks the page as allocated\npage last free pid 9778 tgid 9778 stack trace:\n\nMemory state around the buggy address:\n ffff8881131e1380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n ffff8881131e1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n\u003effff8881131e1480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n                         ^\n ffff8881131e1500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n ffff8881131e1580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n==================================================================\n[1]: https://gist.github.com/mrpre/f683f244544f7b11e7fa87df9e6c2eeb\n[2]: https://lore.kernel.org/linux-serial/20260204074327.226165-1-jiayuan.chen@linux.dev/T/#u","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":"serial: caif: fix use-after-free in caif_serial ldisc_close()","id":"CVE-2026-45866","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":8,"next":{"headline":"power: supply: act8945a: Fix use-after-free in power_supply_changed()","id":"CVE-2026-45867"},"packages":[],"prev":{"headline":"mctp i2c: initialise event handler read bytes","id":"CVE-2026-45865"},"products":["Linux"],"published":"2026-05-27","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":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-05-27","vendors":["Linux"]},"summary":"A use-after-free vulnerability in the Linux kernel's CAIF serial driver allows attackers to execute arbitrary code or escalate privileges via a race condition.","url":"https://insights.sbomify.com/CVE-2026-45866/"}