CVE-2021-47394— netfilter: nf_tables: unlink table before deleting it
Affected Version Matrix 6
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I. Basic Information for CVE-2021-47394
Vulnerability Information
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Vulnerability Title
netfilter: nf_tables: unlink table before deleting it
Source: NVD (National Vulnerability Database)
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: unlink table before deleting it syzbot reports following UAF: BUG: KASAN: use-after-free in memcmp+0x18f/0x1c0 lib/string.c:955 nla_strcmp+0xf2/0x130 lib/nlattr.c:836 nft_table_lookup.part.0+0x1a2/0x460 net/netfilter/nf_tables_api.c:570 nft_table_lookup net/netfilter/nf_tables_api.c:4064 [inline] nf_tables_getset+0x1b3/0x860 net/netfilter/nf_tables_api.c:4064 nfnetlink_rcv_msg+0x659/0x13f0 net/netfilter/nfnetlink.c:285 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504 Problem is that all get operations are lockless, so the commit_mutex held by nft_rcv_nl_event() isn't enough to stop a parallel GET request from doing read-accesses to the table object even after synchronize_rcu(). To avoid this, unlink the table first and store the table objects in on-stack scratch space.
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于netfilter:nf_tables模块删除表之前取消链接表。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2021-47394
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Other References for CVE-2021-47394 (2)
Same Patch Batch · Linux · 2024-05-21 · 361 CVEs total
| CVE-2021-47432 | lib/generic-radix-tree.c: Don't overflow in peek() | |
| CVE-2023-52760 | gfs2: Fix slab-use-after-free in gfs2_qd_dealloc | |
| CVE-2023-52757 | smb: client: fix potential deadlock when releasing mids | |
| CVE-2023-52755 | ksmbd: fix slab out of bounds write in smb_inherit_dacl() | |
| CVE-2023-52754 | media: imon: fix access to invalid resource for the second interface | |
| CVE-2023-52753 | drm/amd/display: Avoid NULL dereference of timing generator | |
| CVE-2023-52752 | smb: client: fix use-after-free bug in cifs_debug_data_proc_show() | |
| CVE-2023-52751 | smb: client: fix use-after-free in smb2_query_info_compound() | |
| CVE-2023-52750 | arm64: Restrict CPU_BIG_ENDIAN to GNU as or LLVM IAS 15.x or newer | |
| CVE-2023-52749 | spi: Fix null dereference on suspend | |
| CVE-2023-52748 | f2fs: avoid format-overflow warning | |
| CVE-2022-48710 | drm/radeon: fix a possible null pointer dereference | |
| CVE-2023-52742 | net: USB: Fix wrong-direction WARNING in plusb.c | |
| CVE-2023-52738 | drm/amdgpu/fence: Fix oops due to non-matching drm_sched init/fini | |
| CVE-2023-52740 | powerpc/64s/interrupt: Fix interrupt exit race with security mitigation switch | |
| CVE-2023-52739 | Fix page corruption caused by racy check in __free_pages | |
| CVE-2023-52741 | cifs: Fix use-after-free in rdata->read_into_pages() | |
| CVE-2023-52743 | ice: Do not use WQ_MEM_RECLAIM flag for workqueue | |
| CVE-2023-52746 | xfrm/compat: prevent potential spectre v1 gadget in xfrm_xlate32_attr() | |
| CVE-2023-52747 | IB/hfi1: Restore allocated resources on failed copyout |
Showing top 20 of 361 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
Same product: Linux
- CVE-2026-45836
Bluetooth: L2CAP: Fix null-ptr-deref in l2cap_sock_get_sndti - CVE-2026-45835
Bluetooth: L2CAP: Fix null-ptr-deref in l2cap_sock_new_conne - CVE-2026-45834
Bluetooth: L2CAP: Fix null-ptr-deref in l2cap_sock_state_cha - CVE-2026-46300
net: skbuff: preserve shared-frag marker during coalescing - CVE-2026-43503
net: skbuff: propagate shared-frag marker through frag-trans
Same vendor: Linux
- CVE-2026-45836
Bluetooth: L2CAP: Fix null-ptr-deref in l2cap_sock_get_sndti - CVE-2026-45835
Bluetooth: L2CAP: Fix null-ptr-deref in l2cap_sock_new_conne - CVE-2026-45834
Bluetooth: L2CAP: Fix null-ptr-deref in l2cap_sock_state_cha - CVE-2026-46300
net: skbuff: preserve shared-frag marker during coalescing - CVE-2026-43503
net: skbuff: propagate shared-frag marker through frag-trans
V. Comments for CVE-2021-47394
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