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CVE-2021-46986— usb: dwc3: gadget: Free gadget structure only after freeing endpoints

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 0.23% · P13

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux e81a7018d93a7de31a3f121c9a7eecd0a5ec58b0< 1ea775021282d90e1d08d696b7ab54aa75d688e5 affected
e81a7018d93a7de31a3f121c9a7eecd0a5ec58b0< bc0cdd72493236fb72b390ad38ce581e353c143c affected
e81a7018d93a7de31a3f121c9a7eecd0a5ec58b0< b4b8e9601d7ee8806d2687f081a42485d27674a1 affected
e81a7018d93a7de31a3f121c9a7eecd0a5ec58b0< bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139 affected
5.10 affected
< 5.10 unaffected
5.10.38≤ 5.10.* unaffected
5.11.22≤ 5.11.* unaffected
… +2 more rows
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I. Basic Information for CVE-2021-46986

Vulnerability Information
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Vulnerability Title
usb: dwc3: gadget: Free gadget structure only after freeing endpoints
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: usb: dwc3: gadget: Free gadget structure only after freeing endpoints As part of commit e81a7018d93a ("usb: dwc3: allocate gadget structure dynamically") the dwc3_gadget_release() was added which will free the dwc->gadget structure upon the device's removal when usb_del_gadget_udc() is called in dwc3_gadget_exit(). However, simply freeing the gadget results a dangling pointer situation: the endpoints created in dwc3_gadget_init_endpoints() have their dep->endpoint.ep_list members chained off the list_head anchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed, the first dwc3_ep in the list now has a dangling prev pointer and likewise for the next pointer of the dwc3_ep at the tail of the list. The dwc3_gadget_free_endpoints() that follows will result in a use-after-free when it calls list_del(). This was caught by enabling KASAN and performing a driver unbind. The recent commit 568262bf5492 ("usb: dwc3: core: Add shutdown callback for dwc3") also exposes this as a panic during shutdown. There are a few possibilities to fix this. One could be to perform a list_del() of the gadget->ep_list itself which removes it from the rest of the dwc3_ep chain. Another approach is what this patch does, by splitting up the usb_del_gadget_udc() call into its separate "del" and "put" components. This allows dwc3_gadget_free_endpoints() to be called before the gadget is finally freed with usb_put_gadget().
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 e81a7018d93a7de31a3f121c9a7eecd0a5ec58b0 ~ 1ea775021282d90e1d08d696b7ab54aa75d688e5 -
Linux Linux 5.10 -

II. Public POCs for CVE-2021-46986

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III. Intelligence Information for CVE-2021-46986

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Other References for CVE-2021-46986 (3)

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

CVE-2021-47013 9.8 CRITICAL net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send
CVE-2021-47036 9.8 CRITICAL udp: skip L4 aggregation for UDP tunnel packets
CVE-2021-46999 9.8 CRITICAL sctp: do asoc update earlier in sctp_sf_do_dupcook_a
CVE-2021-47035 8.8 HIGH iommu/vt-d: Remove WO permissions on second-level paging entries
CVE-2021-47017 8.8 HIGH ath10k: Fix a use after free in ath10k_htc_send_bundle
CVE-2021-47049 8.4 HIGH Drivers: hv: vmbus: Use after free in __vmbus_open()
CVE-2021-47014 7.8 HIGH net/sched: act_ct: fix wild memory access when clearing fragments
CVE-2020-36785 7.8 HIGH media: atomisp: Fix use after free in atomisp_alloc_css_stat_bufs()
CVE-2021-47040 7.8 HIGH io_uring: fix overflows checks in provide buffers
CVE-2021-47048 7.8 HIGH spi: spi-zynqmp-gqspi: fix use-after-free in zynqmp_qspi_exec_op
CVE-2021-46984 7.8 HIGH kyber: fix out of bounds access when preempted
CVE-2021-46993 7.8 HIGH sched: Fix out-of-bound access in uclamp
CVE-2021-46998 7.8 HIGH ethernet:enic: Fix a use after free bug in enic_hard_start_xmit
CVE-2021-46992 7.8 HIGH netfilter: nftables: avoid overflows in nft_hash_buckets()
CVE-2021-46977 7.8 HIGH KVM: VMX: Disable preemption when probing user return MSRs
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-2021-46983 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-2021-46986

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