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CVE-2021-47396— mac80211-hwsim: fix late beacon hrtimer handling

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mac80211-hwsim模块会延迟处理hrtimer。

AI Predicted 5.5 Difficulty: Trivial EPSS 0.24% · P15

Possible ATT&CK Techniques 1 AI

T1498 · Network Denial of Service

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 01e59e467ecf976c782eecd4dc99644802cc60e2< 9bee85de2c8155388c09a2e1530a243ec1c96f05 affected
01e59e467ecf976c782eecd4dc99644802cc60e2< 2c204cf594df3b9468368dc9d0b24d482d93cda7 affected
01e59e467ecf976c782eecd4dc99644802cc60e2< ed2adf69e29848d1eb9df99633dde655421c92ed affected
01e59e467ecf976c782eecd4dc99644802cc60e2< 313bbd1990b6ddfdaa7da098d0c56b098a833572 affected
3.9 affected
< 3.9 unaffected
5.4.151≤ 5.4.* unaffected
5.10.71≤ 5.10.* unaffected
… +2 more rows
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I. Basic Information for CVE-2021-47396

Vulnerability Information
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Vulnerability Title
mac80211-hwsim: fix late beacon hrtimer handling
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: mac80211-hwsim: fix late beacon hrtimer handling Thomas explained in https://lore.kernel.org/r/87mtoeb4hb.ffs@tglx that our handling of the hrtimer here is wrong: If the timer fires late (e.g. due to vCPU scheduling, as reported by Dmitry/syzbot) then it tries to actually rearm the timer at the next deadline, which might be in the past already: 1 2 3 N N+1 | | | ... | | ^ intended to fire here (1) ^ next deadline here (2) ^ actually fired here The next time it fires, it's later, but will still try to schedule for the next deadline (now 3), etc. until it catches up with N, but that might take a long time, causing stalls etc. Now, all of this is simulation, so we just have to fix it, but note that the behaviour is wrong even per spec, since there's no value then in sending all those beacons unaligned - they should be aligned to the TBTT (1, 2, 3, ... in the picture), and if we're a bit (or a lot) late, then just resume at that point. Therefore, change the code to use hrtimer_forward_now() which will ensure that the next firing of the timer would be at N+1 (in the picture), i.e. the next interval point after the current time.
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mac80211-hwsim模块会延迟处理hrtimer。
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 01e59e467ecf976c782eecd4dc99644802cc60e2 ~ 9bee85de2c8155388c09a2e1530a243ec1c96f05 -
Linux Linux 3.9 -

II. Public POCs for CVE-2021-47396

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III. Intelligence Information for CVE-2021-47396

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Other References for CVE-2021-47396 (4)

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

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-2021-47427 9.8 CRITICAL scsi: iscsi: Fix iscsi_task use after free
CVE-2021-47378 9.8 CRITICAL nvme-rdma: destroy cm id before destroy qp to avoid use after free
CVE-2023-52741 9.8 CRITICAL cifs: Fix use-after-free in rdata->read_into_pages()
CVE-2021-47232 9.8 CRITICAL can: j1939: fix Use-after-Free, hold skb ref while in use
CVE-2021-47328 9.8 CRITICAL scsi: iscsi: Fix conn use after free during resets
CVE-2021-47308 8.8 HIGH scsi: libfc: Fix array index out of bound exception
CVE-2023-52798 8.8 HIGH wifi: ath11k: fix dfs radar event locking
CVE-2023-52776 8.8 HIGH wifi: ath12k: fix dfs-radar and temperature event locking
CVE-2021-47390 8.8 HIGH KVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect()
CVE-2023-52790 8.8 HIGH swiotlb: fix out-of-bounds TLB allocations with CONFIG_SWIOTLB_DYNAMIC
CVE-2023-52769 8.8 HIGH wifi: ath12k: fix htt mlo-offset event locking
CVE-2023-52801 8.8 HIGH iommufd: Fix missing update of domains_itree after splitting iopt_area
CVE-2021-47388 8.8 HIGH mac80211: fix use-after-free in CCMP/GCMP RX
CVE-2023-52846 8.8 HIGH hsr: Prevent use after free in prp_create_tagged_frame()
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-2023-52829 8.4 HIGH wifi: ath12k: fix possible out-of-bound write in ath12k_wmi_ext_hal_reg_caps()
CVE-2021-47245 8.2 HIGH netfilter: synproxy: Fix out of bounds when parsing TCP options

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-2021-47396

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