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: mm: memcontrol: slab: fix obtain a     reference to a freeing memcg Patch series Use obj_cgroup APIs to charge kmem pages, v5. Since Roman's     series The new cgroup slab memory controller applied. All slab objects are charged with the new APIs of     obj_cgroup. The new APIs introduce a struct obj_cgroup to charge slab objects. It prevents long-living     objects from pinning the original memory cgroup in the memory. But there are still some corner objects     (e.g. allocations larger than order-1 page on SLUB) which are not charged with the new APIs. Those objects     (include the pages which are allocated from buddy allocator directly) are charged as kmem pages which     still hold a reference to the memory cgroup. E.g. We know that the kernel stack is charged as kmem pages     because the size of the kernel stack can be greater than 2 pages (e.g. 16KB on x86_64 or arm64). If we     create a thread (suppose the thread stack is charged to memory cgroup A) and then move it from memory     cgroup A to memory cgroup B. Because the kernel stack of the thread hold a reference to the memory cgroup     A. The thread can pin the memory cgroup A in the memory even if we remove the cgroup A. If we want to see     this scenario by using the following script. We can see that the system has added 500 dying cgroups (This     is not a real world issue, just a script to show that the large kmallocs are charged as kmem pages which     can pin the memory cgroup in the memory). #!/bin/bash cat /proc/cgroups | grep memory cd     /sys/fs/cgroup/memory echo 1 > memory.move_charge_at_immigrate for i in range{1..500} do mkdir kmem_test     echo $$ > kmem_test/cgroup.procs sleep 3600 & echo $$ > cgroup.procs echo `cat kmem_test/cgroup.procs` >     cgroup.procs rmdir kmem_test done cat /proc/cgroups | grep memory This patchset aims to make those kmem     pages to drop the reference to memory cgroup by using the APIs of obj_cgroup. Finally, we can see that the     number of the dying cgroups will not increase if we run the above test script. This patch (of 7): The     rcu_read_lock/unlock only can guarantee that the memcg will not be freed, but it cannot guarantee the     success of css_get (which is in the refill_stock when cached memcg changed) to memcg. rcu_read_lock()     memcg = obj_cgroup_memcg(old) __memcg_kmem_uncharge(memcg) refill_stock(memcg) if (stock->cached != memcg)     // css_get can change the ref counter from 0 back to 1. css_get(&memcg->css) rcu_read_unlock() This fix is     very like the commit: eefbfa7fd678 (mm: memcg/slab: fix use after free in obj_cgroup_charge) Fix this by     holding a reference to the memcg which is passed to the __memcg_kmem_uncharge() before calling
    __memcg_kmem_uncharge(). (CVE-2021-47011)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Published	Updated	Severity
230211	Linux Distros Unpatched Vulnerability : CVE-2021-47011	Nessus	Misc.	3/5/2025	3/5/2025	medium
160459	Amazon Linux 2 : kernel (ALASKERNEL-5.10-2022-002)	Nessus	Amazon Linux Local Security Checks	5/2/2022	3/17/2025	high

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