The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - In the Linux kernel, the following vulnerability has been resolved: aio: fix use-after-free due to missing     POLLFREE handling signalfd_poll() and binder_poll() are special in that they use a waitqueue whose     lifetime is the current task, rather than the struct file as is normally the case. This is okay for     blocking polls, since a blocking poll occurs within one task; however, non-blocking polls require another     solution. This solution is for the queue to be cleared before it is freed, by sending a POLLFREE     notification to all waiters. Unfortunately, only eventpoll handles POLLFREE. A second type of non-blocking     poll, aio poll, was added in kernel v4.18, and it doesn't handle POLLFREE. This allows a use-after-free to     occur if a signalfd or binder fd is polled with aio poll, and the waitqueue gets freed. Fix this by making     aio poll handle POLLFREE. A patch by Ramji Jiyani <ramjiyani@google.com>     (https://lore.kernel.org/r/20211027011834.2497484-1-ramjiyani@google.com) tried to do this by making     aio_poll_wake() always complete the request inline if POLLFREE is seen. However, that solution had two     bugs. First, it introduced a deadlock, as it unconditionally locked the aio context while holding the     waitqueue lock, which inverts the normal locking order. Second, it didn't consider that POLLFREE     notifications are missed while the request has been temporarily de-queued. The second problem was solved     by my previous patch. This patch then properly fixes the use-after-free by handling POLLFREE in a     deadlock-free way. It does this by taking advantage of the fact that freeing of the waitqueue is RCU-     delayed, similar to what eventpoll does. (CVE-2021-47505)

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Linux Distros Unpatched Vulnerability : CVE-2021-47505

high Nessus Plugin ID 224354

Version 1.9

Version 1.8

Version 1.6

Version 1.5

Version 1.1

Version 1.9 Oct 28, 2025, 5:56 PM Detection (updated detection logic) Plugin Feed: 202510281756
Version 1.8 Oct 27, 2025, 11:56 PM CVSS temporal metrics ("CVSSv2 temporal vector" set to "CVSS2#E:U/RL:U/RC:C") CVSS temporal metrics ("CVSSv3 temporal vector" set to "CVSS:3.0/E:U/RL:U/RC:C") Detection (updated detection logic) Plugin Feed: 202510272356
Version 1.6 Sep 30, 2025, 5:08 PM Detection (updated detection logic) Plugin metadata Plugin Feed: 202509301708
Version 1.5 Sep 25, 2025, 11:29 PM Detection (updated detection logic) Plugin metadata Plugin Feed: 202509252329
Version 1.1 Mar 5, 2025, 8:29 AM New Plugin Feed: 202503050829