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CVE-2021-47013— net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send

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 emac_mac_tx_buf_send 中存在释放后的重用。

CVSS 9.8 · Critical EPSS 0.78% · P53

Possible ATT&CK Techniques 1 AI

T1068 · Exploitation for Privilege Escalation

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux b9b17debc69d27cd55e21ee51a5ba7fc50a426cf< c7f75d11fe72913d2619f97b2334b083cd7bb955 affected
b9b17debc69d27cd55e21ee51a5ba7fc50a426cf< dc1b438a35773d030be0ee80d9c635c3e558a322 affected
b9b17debc69d27cd55e21ee51a5ba7fc50a426cf< 16d8c44be52e3650917736d45f5904384a9da834 affected
b9b17debc69d27cd55e21ee51a5ba7fc50a426cf< 55fcdd1258faaecca74b91b88cc0921f9edd775d affected
b9b17debc69d27cd55e21ee51a5ba7fc50a426cf< 9dc373f74097edd0e35f3393d6248eda8d1ba99d affected
b9b17debc69d27cd55e21ee51a5ba7fc50a426cf< 8c06f34785068b87e2b560534c77c163d6c6dca7 affected
b9b17debc69d27cd55e21ee51a5ba7fc50a426cf< e407495ba6788a67d1bd41714158c079e340879b affected
b9b17debc69d27cd55e21ee51a5ba7fc50a426cf< 6d72e7c767acbbdd44ebc7d89c6690b405b32b57 affected
… +10 more rows
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I. Basic Information for CVE-2021-47013

Vulnerability Information
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Vulnerability Title
net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send In emac_mac_tx_buf_send, it calls emac_tx_fill_tpd(..,skb,..). If some error happens in emac_tx_fill_tpd(), the skb will be freed via dev_kfree_skb(skb) in error branch of emac_tx_fill_tpd(). But the freed skb is still used via skb->len by netdev_sent_queue(,skb->len). As i observed that emac_tx_fill_tpd() haven't modified the value of skb->len, thus my patch assigns skb->len to 'len' before the possible free and use 'len' instead of skb->len later.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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 emac_mac_tx_buf_send 中存在释放后的重用。
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 b9b17debc69d27cd55e21ee51a5ba7fc50a426cf ~ c7f75d11fe72913d2619f97b2334b083cd7bb955 -
Linux Linux 4.9 -

II. Public POCs for CVE-2021-47013

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III. Intelligence Information for CVE-2021-47013

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Other References for CVE-2021-47013 (7)

Same Patch Batch · Linux · 2024-02-28 · 86 CVEs total

CVE-2021-46999 9.8 CRITICAL sctp: do asoc update earlier in sctp_sf_do_dupcook_a
CVE-2021-47036 9.8 CRITICAL udp: skip L4 aggregation for UDP tunnel packets
CVE-2021-47017 8.8 HIGH ath10k: Fix a use after free in ath10k_htc_send_bundle
CVE-2021-47035 8.8 HIGH iommu/vt-d: Remove WO permissions on second-level paging entries
CVE-2021-47049 8.4 HIGH Drivers: hv: vmbus: Use after free in __vmbus_open()
CVE-2021-46992 7.8 HIGH netfilter: nftables: avoid overflows in nft_hash_buckets()
CVE-2021-46998 7.8 HIGH ethernet:enic: Fix a use after free bug in enic_hard_start_xmit
CVE-2021-47048 7.8 HIGH spi: spi-zynqmp-gqspi: fix use-after-free in zynqmp_qspi_exec_op
CVE-2021-46993 7.8 HIGH sched: Fix out-of-bound access in uclamp
CVE-2020-36785 7.8 HIGH media: atomisp: Fix use after free in atomisp_alloc_css_stat_bufs()
CVE-2021-46984 7.8 HIGH kyber: fix out of bounds access when preempted
CVE-2021-47040 7.8 HIGH io_uring: fix overflows checks in provide buffers
CVE-2021-46977 7.8 HIGH KVM: VMX: Disable preemption when probing user return MSRs
CVE-2021-47014 7.8 HIGH net/sched: act_ct: fix wild memory access when clearing fragments
CVE-2021-47012 7.8 HIGH RDMA/siw: Fix a use after free in siw_alloc_mr
CVE-2021-47011 7.8 HIGH mm: memcontrol: slab: fix obtain a reference to a freeing memcg
CVE-2020-36787 7.8 HIGH media: aspeed: fix clock handling logic
CVE-2021-47041 7.5 HIGH nvmet-tcp: fix incorrect locking in state_change sk callback
CVE-2021-47001 7.5 HIGH xprtrdma: Fix cwnd update ordering
CVE-2021-46983 7.5 HIGH nvmet-rdma: Fix NULL deref when SEND is completed with error

Showing top 20 of 86 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-47013

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