{"vulnerability": "CVE-2022-50220", "sightings": [{"uuid": "0075c56d-99e5-49c6-9b76-2332c5f71a88", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "2a075640-a300-48a4-bb44-bc6130783b9b", "vulnerability": "CVE-2022-50220", "type": "seen", "source": "https://t.me/DarkWebInformer_CVEAlerts/18730", "content": "\ud83d\udd17 DarkWebInformer.com - Cyber Threat Intelligence\n\ud83d\udccc CVE ID: CVE-2022-50220\n\ud83d\udd25 CVSS Score: N/A\n\ud83d\udd39 Description: In the Linux kernel, the following vulnerability has been resolved:\n\nusbnet: Fix linkwatch use-after-free on disconnect\n\nusbnet uses the work usbnet_deferred_kevent() to perform tasks which may\nsleep.  On disconnect, completion of the work was originally awaited in\n->ndo_stop().  But in 2003, that was moved to ->disconnect() by historic\ncommit \"[PATCH] USB: usbnet, prevent exotic rtnl deadlock\":\n\n  https://git.kernel.org/tglx/history/c/0f138bbfd83c\n\nThe change was made because back then, the kernel's workqueue\nimplementation did not allow waiting for a single work.  One had to wait\nfor completion of *all* work by calling flush_scheduled_work(), and that\ncould deadlock when waiting for usbnet_deferred_kevent() with rtnl_mutex\nheld in ->ndo_stop().\n\nThe commit solved one problem but created another:  It causes a\nuse-after-free in USB Ethernet drivers aqc111.c, asix_devices.c,\nax88179_178a.c, ch9200.c and smsc75xx.c:\n\n* If the drivers receive a link change interrupt immediately before\n  disconnect, they raise EVENT_LINK_RESET in their (non-sleepable)\n  ->status() callback and schedule usbnet_deferred_kevent().\n* usbnet_deferred_kevent() invokes the driver's ->link_reset() callback,\n  which calls netif_carrier_{on,off}().\n* That in turn schedules the work linkwatch_event().\n\nBecause usbnet_deferred_kevent() is awaited after unregister_netdev(),\nnetif_carrier_{on,off}() may operate on an unregistered netdev and\nlinkwatch_event() may run after free_netdev(), causing a use-after-free.\n\nIn 2010, usbnet was changed to only wait for a single instance of\nusbnet_deferred_kevent() instead of *all* work by commit 23f333a2bfaf\n(\"drivers/net: don't use flush_scheduled_work()\").\n\nUnfortunately the commit neglected to move the wait back to\n->ndo_stop().  Rectify that omission at long last.\n\ud83d\udccf Published: 2025-06-18T11:03:55.461Z\n\ud83d\udccf Modified: 2025-06-18T11:03:55.461Z\n\ud83d\udd17 References:\n1. https://git.kernel.org/stable/c/d2d6b530d89b0a912148018027386aa049f0a309\n2. https://git.kernel.org/stable/c/e2a521a7dcc463c5017b4426ca0804e151faeff7\n3. https://git.kernel.org/stable/c/7f77dcbc030c2faa6d8e8a594985eeb34018409e\n4. https://git.kernel.org/stable/c/8b4588b8b00b299be16a35be67b331d8fdba03f3\n5. https://git.kernel.org/stable/c/135199a2edd459d2b123144efcd7f9bcd95128e4\n6. https://git.kernel.org/stable/c/635fd8953e4309b54ca6a81bed1d4a87668694f4\n7. https://git.kernel.org/stable/c/d49bb8cf9bfaa06aa527eb30f1a52a071da2e32f\n8. https://git.kernel.org/stable/c/db3b738ae5f726204876f4303c49cfdf4311403f\n9. https://git.kernel.org/stable/c/a69e617e533edddf3fa3123149900f36e0a6dc74", "creation_timestamp": "2025-06-18T11:38:34.000000Z"}, {"uuid": "6620ad5d-7359-4f7c-9743-ba582efa7340", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "2a075640-a300-48a4-bb44-bc6130783b9b", "vulnerability": "CVE-2022-50220", "type": "seen", "source": "https://bsky.app/profile/cve.skyfleet.blue/post/3lrvgima3eb2k", "content": "", "creation_timestamp": "2025-06-18T16:28:07.319818Z"}]}