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CVE-2021-47452— netfilter: nf_tables: skip netdev events generated on netns removal

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

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。目前尚无此漏洞的相关信息，请随时关注CNNVD或厂商公告。

AI Predicted 5.5 Difficulty: Moderate EPSS 0.20% · P9

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 767d1216bff82507c945e92fe719dff2083bb2f4< 90c7c58aa2bd02c65a4c63b7dfe0b16eab12cf9f affected
767d1216bff82507c945e92fe719dff2083bb2f4< 68a3765c659f809dcaac20030853a054646eb739 affected
b110391d1e806167254d3c7ae5d637191d913175 affected
0a0e5d47670b753d3dbf88f3c77a97a30864d9bd affected
5.4.99< 5.5 affected
5.10.17< 5.11 affected
5.11 affected
< 5.11 unaffected
… +2 more rows
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I. Basic Information for CVE-2021-47452

Vulnerability Information
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Vulnerability Title
netfilter: nf_tables: skip netdev events generated on netns removal
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: skip netdev events generated on netns removal syzbot reported following (harmless) WARN: WARNING: CPU: 1 PID: 2648 at net/netfilter/core.c:468 nft_netdev_unregister_hooks net/netfilter/nf_tables_api.c:230 [inline] nf_tables_unregister_hook include/net/netfilter/nf_tables.h:1090 [inline] __nft_release_basechain+0x138/0x640 net/netfilter/nf_tables_api.c:9524 nft_netdev_event net/netfilter/nft_chain_filter.c:351 [inline] nf_tables_netdev_event+0x521/0x8a0 net/netfilter/nft_chain_filter.c:382 reproducer: unshare -n bash -c 'ip link add br0 type bridge; nft add table netdev t ; \ nft add chain netdev t ingress \{ type filter hook ingress device "br0" \ priority 0\; policy drop\; \}' Problem is that when netns device exit hooks create the UNREGISTER event, the .pre_exit hook for nf_tables core has already removed the base hook. Notifier attempts to do this again. The need to do base hook unregister unconditionally was needed in the past, because notifier was last stage where reg->dev dereference was safe. Now that nf_tables does the hook removal in .pre_exit, this isn't needed anymore.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
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。目前尚无此漏洞的相关信息，请随时关注CNNVD或厂商公告。
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

Vendor Product Affected Versions CPE Subscribe
Linux Linux 767d1216bff82507c945e92fe719dff2083bb2f4 ~ 90c7c58aa2bd02c65a4c63b7dfe0b16eab12cf9f -
Linux Linux 5.11 -

II. Public POCs for CVE-2021-47452

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III. Intelligence Information for CVE-2021-47452

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Other References for CVE-2021-47452 (2)

Same Patch Batch · Linux · 2024-05-22 · 63 CVEs total

CVE-2021-47496 9.8 CRITICAL net/tls: Fix flipped sign in tls_err_abort() calls
CVE-2021-47478 9.1 CRITICAL isofs: Fix out of bound access for corrupted isofs image
CVE-2021-47450 8.8 HIGH KVM: arm64: Fix host stage-2 PGD refcount
CVE-2021-47433 8.1 HIGH btrfs: fix abort logic in btrfs_replace_file_extents
CVE-2021-47446 7.8 HIGH drm/msm/a4xx: fix error handling in a4xx_gpu_init()
CVE-2021-47493 7.8 HIGH ocfs2: fix race between searching chunks and release journal_head from buffer_head
CVE-2021-47492 7.8 HIGH mm, thp: bail out early in collapse_file for writeback page
CVE-2021-47494 7.8 HIGH cfg80211: fix management registrations locking
CVE-2021-47451 7.8 HIGH netfilter: xt_IDLETIMER: fix panic that occurs when timer_type has garbage value
CVE-2021-47447 7.8 HIGH drm/msm/a3xx: fix error handling in a3xx_gpu_init()
CVE-2021-47485 7.8 HIGH IB/qib: Protect from buffer overflow in struct qib_user_sdma_pkt fields
CVE-2021-47483 7.8 HIGH regmap: Fix possible double-free in regcache_rbtree_exit()
CVE-2021-47459 7.8 HIGH can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv
CVE-2021-47461 7.8 HIGH userfaultfd: fix a race between writeprotect and exit_mmap()
CVE-2021-47448 7.5 HIGH mptcp: fix possible stall on recvmsg()
CVE-2021-47438 7.1 HIGH net/mlx5e: Fix memory leak in mlx5_core_destroy_cq() error path
CVE-2021-47465 7.1 HIGH KVM: PPC: Book3S HV: Fix stack handling in idle_kvm_start_guest()
CVE-2021-47458 7.1 HIGH ocfs2: mount fails with buffer overflow in strlen
CVE-2021-47498 dm rq: don't queue request to blk-mq during DM suspend
CVE-2021-47497 nvmem: Fix shift-out-of-bound (UBSAN) with byte size cells

Showing top 20 of 63 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-47452

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