CVE-2021-47299: In the Linux kernel, the following vulnerability has been resolved: xdp, net: Fix use-after-free in bpf_xdp_link_release The problem occurs between…

PriorityP420medium5.5CVSS 3.1

AVLACLPRLUINSUCNINAH

EPSS

0.23%

13.3th percentile

In the Linux kernel, the following vulnerability has been resolved: xdp, net: Fix use-after-free in bpf_xdp_link_release The problem occurs between dev_get_by_index() and dev_xdp_attach_link(). At this point, dev_xdp_uninstall() is called. Then xdp link will not be detached automatically when dev is released. But link->dev already points to dev, when xdp link is released, dev will still be accessed, but dev has been released. dev_get_by_index() | link->dev = dev | | rtnl_lock() | unregister_netdevice_many() | dev_xdp_uninstall() | rtnl_unlock() rtnl_lock(); | dev_xdp_attach_link() | rtnl_unlock(); | | netdev_run_todo() // dev released bpf_xdp_link_release() | /* access dev. | use-after-free */ | [ 45.966867] BUG: KASAN: use-after-free in bpf_xdp_link_release+0x3b8/0x3d0 [ 45.967619] Read of size 8 at addr ffff00000f9980c8 by task a.out/732 [ 45.968297] [ 45.968502] CPU: 1 PID: 732 Comm: a.out Not tainted 5.13.0+ #22 [ 45.969222] Hardware name: linux,dummy-virt (DT) [ 45.969795] Call trace: [ 45.970106] dump_backtrace+0x0/0x4c8 [ 45.970564] show_stack+0x30/0x40 [ 45.970981] dump_stack_lvl+0x120/0x18c [ 45.971470] print_address_description.constprop.0+0x74/0x30c [ 45.972182] kasan_report+0x1e8/0x200 [ 45.972659] __asan_report_load8_noabort+0x2c/0x50 [ 45.973273] bpf_xdp_link_release+0x3b8/0x3d0 [ 45.973834] bpf_link_free+0xd0/0x188 [ 45.974315] bpf_link_put+0x1d0/0x218 [ 45.974790] bpf_link_release+0x3c/0x58 [ 45.975291] __fput+0x20c/0x7e8 [ 45.975706] ____fput+0x24/0x30 [ 45.976117] task_work_run+0x104/0x258 [ 45.976609] do_notify_resume+0x894/0xaf8 [ 45.977121] work_pending+0xc/0x328 [ 45.977575] [ 45.977775] The buggy address belongs to the page: [ 45.978369] page:fffffc00003e6600 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4f998 [ 45.979522] flags: 0x7fffe0000000000(node=0|zone=0|lastcpupid=0x3ffff) [ 45.980349] raw: 07fffe0000000000 fffffc00003e6708 ffff0000dac3c010 0000000000000000 [ 45.981309] raw: 0000000000000000 0000000000000000 000000

Affected

12 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 5.14.6-1 (bookworm)	linux 5.14.6-1 (bookworm)
linux	linux	—	—
linux	linux	>= aa8d3a716b59db6c1ad6c68fb8aa05e31980da60 < ca9ba1de8f09976b45ccc8e655c51c6201992139	ca9ba1de8f09976b45ccc8e655c51c6201992139
linux	linux	>= aa8d3a716b59db6c1ad6c68fb8aa05e31980da60 < a7537dc73e69ad9c0b67ad24ad3ebee954ed0af6	a7537dc73e69ad9c0b67ad24ad3ebee954ed0af6
linux	linux	>= aa8d3a716b59db6c1ad6c68fb8aa05e31980da60 < 5acc7d3e8d342858405fbbc671221f676b547ce7	5acc7d3e8d342858405fbbc671221f676b547ce7
linux	linux_kernel	—	—
linux	linux_kernel	>= 0 < 5.10.70-1	5.10.70-1
linux	linux_kernel	>= 0 < 5.14.6-1	5.14.6-1
linux	linux_kernel	>= 0 < 5.14.6-1	5.14.6-1
linux	linux_kernel	>= 0 < 5.14.6-1	5.14.6-1
linux	linux_kernel	>= 5.11 < 5.13.6	5.13.6
linux	linux_kernel	>= 5.9 < 5.10.54	5.10.54

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv5.5MEDIUM

vendor_debian5.5MEDIUM

vendor_redhat5.5MEDIUM

Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.