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CVE-2021-47363— nexthop: Fix division by zero while replacing a resilient group

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，该漏洞源于存在除以零的问题。

AI Predicted 5.5 Difficulty: Hard EPSS 0.21% · P10

Affected Version Matrix 6

VendorProduct Version RangeStatus
Linux Linux 283a72a5599e80750699d2021830a294ed9ab3f3< e9d32ec26e7f01d1af13bdc687f586362546aa25 affected
283a72a5599e80750699d2021830a294ed9ab3f3< 563f23b002534176f49524b5ca0e1d94d8906c40 affected
5.13 affected
< 5.13 unaffected
5.14.9≤ 5.14.* unaffected
5.15≤ * unaffected
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I. Basic Information for CVE-2021-47363

Vulnerability Information
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Vulnerability Title
nexthop: Fix division by zero while replacing a resilient group
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: nexthop: Fix division by zero while replacing a resilient group The resilient nexthop group torture tests in fib_nexthop.sh exposed a possible division by zero while replacing a resilient group [1]. The division by zero occurs when the data path sees a resilient nexthop group with zero buckets. The tests replace a resilient nexthop group in a loop while traffic is forwarded through it. The tests do not specify the number of buckets while performing the replacement, resulting in the kernel allocating a stub resilient table (i.e, 'struct nh_res_table') with zero buckets. This table should never be visible to the data path, but the old nexthop group (i.e., 'oldg') might still be used by the data path when the stub table is assigned to it. Fix this by only assigning the stub table to the old nexthop group after making sure the group is no longer used by the data path. Tested with fib_nexthops.sh: Tests passed: 222 Tests failed: 0 [1] divide error: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 1850 Comm: ping Not tainted 5.14.0-custom-10271-ga86eb53057fe #1107 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-4.fc34 04/01/2014 RIP: 0010:nexthop_select_path+0x2d2/0x1a80 [...] Call Trace: fib_select_multipath+0x79b/0x1530 fib_select_path+0x8fb/0x1c10 ip_route_output_key_hash_rcu+0x1198/0x2da0 ip_route_output_key_hash+0x190/0x340 ip_route_output_flow+0x21/0x120 raw_sendmsg+0x91d/0x2e10 inet_sendmsg+0x9e/0xe0 __sys_sendto+0x23d/0x360 __x64_sys_sendto+0xe1/0x1b0 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae
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，该漏洞源于存在除以零的问题。
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 283a72a5599e80750699d2021830a294ed9ab3f3 ~ e9d32ec26e7f01d1af13bdc687f586362546aa25 -
Linux Linux 5.13 -

II. Public POCs for CVE-2021-47363

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III. Intelligence Information for CVE-2021-47363

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Other References for CVE-2021-47363 (2)

Same Patch Batch · Linux · 2024-05-21 · 361 CVEs total

CVE-2021-47328 9.8 CRITICAL scsi: iscsi: Fix conn use after free during resets
CVE-2023-52741 9.8 CRITICAL cifs: Fix use-after-free in rdata->read_into_pages()
CVE-2023-52732 9.8 CRITICAL ceph: blocklist the kclient when receiving corrupted snap trace
CVE-2023-52755 9.8 CRITICAL ksmbd: fix slab out of bounds write in smb_inherit_dacl()
CVE-2021-47232 9.8 CRITICAL can: j1939: fix Use-after-Free, hold skb ref while in use
CVE-2021-47378 9.8 CRITICAL nvme-rdma: destroy cm id before destroy qp to avoid use after free
CVE-2021-47427 9.8 CRITICAL scsi: iscsi: Fix iscsi_task use after free
CVE-2023-52776 8.8 HIGH wifi: ath12k: fix dfs-radar and temperature event locking
CVE-2023-52846 8.8 HIGH hsr: Prevent use after free in prp_create_tagged_frame()
CVE-2021-47390 8.8 HIGH KVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect()
CVE-2021-47388 8.8 HIGH mac80211: fix use-after-free in CCMP/GCMP RX
CVE-2021-47308 8.8 HIGH scsi: libfc: Fix array index out of bound exception
CVE-2023-52801 8.8 HIGH iommufd: Fix missing update of domains_itree after splitting iopt_area
CVE-2023-52769 8.8 HIGH wifi: ath12k: fix htt mlo-offset event locking
CVE-2023-52798 8.8 HIGH wifi: ath11k: fix dfs radar event locking
CVE-2023-52790 8.8 HIGH swiotlb: fix out-of-bounds TLB allocations with CONFIG_SWIOTLB_DYNAMIC
CVE-2023-52829 8.4 HIGH wifi: ath12k: fix possible out-of-bound write in ath12k_wmi_ext_hal_reg_caps()
CVE-2021-47240 8.4 HIGH net: qrtr: fix OOB Read in qrtr_endpoint_post
CVE-2021-47352 8.4 HIGH virtio-net: Add validation for used length
CVE-2023-52775 8.2 HIGH net/smc: avoid data corruption caused by decline

Showing top 20 of 361 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-47363

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