CVE-2021-47220 Security Vulnerability & Exploit Details

CVE-2021-47220
Vulnerability Scoring

Analysis In Progress

Attack Complexity Details

Attack Complexity:
Attack Complexity Analysis In Progress
Attack Vector:
Attack Vector Under Analysis
Privileges Required: None
No authentication is required for exploitation.
Scope:
Impact is confined to the initially vulnerable component.
User Interaction: None
No user interaction is necessary for exploitation.

CVE-2021-47220 Details

Status: Awaiting Analysis

Last updated: 🕐 03 Oct 2024, 13:15 UTC
Originally published on: 🕒 21 May 2024, 15:15 UTC

Time between publication and last update: 134 days

CVSS Release:

CVE-2021-47220 Vulnerability Summary

CVE-2021-47220: In the Linux kernel, the following vulnerability has been resolved: usb: dwc3: core: fix kernel panic when do reboot When do system reboot, it calls dwc3_shutdown and the whole debugfs for dwc3 has removed first, when the gadget tries to do deinit, and remove debugfs for its endpoints, it meets NULL pointer dereference issue when call debugfs_lookup. Fix it by removing the whole dwc3 debugfs later than dwc3_drd_exit. [ 2924.958838] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000002 .... [ 2925.030994] pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--) [ 2925.037005] pc : inode_permission+0x2c/0x198 [ 2925.041281] lr : lookup_one_len_common+0xb0/0xf8 [ 2925.045903] sp : ffff80001276ba70 [ 2925.049218] x29: ffff80001276ba70 x28: ffff0000c01f0000 x27: 0000000000000000 [ 2925.056364] x26: ffff800011791e70 x25: 0000000000000008 x24: dead000000000100 [ 2925.063510] x23: dead000000000122 x22: 0000000000000000 x21: 0000000000000001 [ 2925.070652] x20: ffff8000122c6188 x19: 0000000000000000 x18: 0000000000000000 [ 2925.077797] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000004 [ 2925.084943] x14: ffffffffffffffff x13: 0000000000000000 x12: 0000000000000030 [ 2925.092087] x11: 0101010101010101 x10: 7f7f7f7f7f7f7f7f x9 : ffff8000102b2420 [ 2925.099232] x8 : 7f7f7f7f7f7f7f7f x7 : feff73746e2f6f64 x6 : 0000000000008080 [ 2925.106378] x5 : 61c8864680b583eb x4 : 209e6ec2d263dbb7 x3 : 000074756f307065 [ 2925.113523] x2 : 0000000000000001 x1 : 0000000000000000 x0 : ffff8000122c6188 [ 2925.120671] Call trace: [ 2925.123119] inode_permission+0x2c/0x198 [ 2925.127042] lookup_one_len_common+0xb0/0xf8 [ 2925.131315] lookup_one_len_unlocked+0x34/0xb0 [ 2925.135764] lookup_positive_unlocked+0x14/0x50 [ 2925.140296] debugfs_lookup+0x68/0xa0 [ 2925.143964] dwc3_gadget_free_endpoints+0x84/0xb0 [ 2925.148675] dwc3_gadget_exit+0x28/0x78 [ 2925.152518] dwc3_drd_exit+0x100/0x1f8 [ 2925.156267] dwc3_remove+0x11c/0x120 [ 2925.159851] dwc3_shutdown+0x14/0x20 [ 2925.163432] platform_shutdown+0x28/0x38 [ 2925.167360] device_shutdown+0x15c/0x378 [ 2925.171291] kernel_restart_prepare+0x3c/0x48 [ 2925.175650] kernel_restart+0x1c/0x68 [ 2925.179316] __do_sys_reboot+0x218/0x240 [ 2925.183247] __arm64_sys_reboot+0x28/0x30 [ 2925.187262] invoke_syscall+0x48/0x100 [ 2925.191017] el0_svc_common.constprop.0+0x48/0xc8 [ 2925.195726] do_el0_svc+0x28/0x88 [ 2925.199045] el0_svc+0x20/0x30 [ 2925.202104] el0_sync_handler+0xa8/0xb0 [ 2925.205942] el0_sync+0x148/0x180 [ 2925.209270] Code: a9025bf5 2a0203f5 121f0056 370802b5 (79400660) [ 2925.215372] ---[ end trace 124254d8e485a58b ]--- [ 2925.220012] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b [ 2925.227676] Kernel Offset: disabled [ 2925.231164] CPU features: 0x00001001,20000846 [ 2925.235521] Memory Limit: none [ 2925.238580] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]---

Assessing the Risk of CVE-2021-47220

Access Complexity Graph

The exploitability of CVE-2021-47220 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2021-47220

No exploitability data is available for CVE-2021-47220.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2021-47220, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2021-47220, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

Confidentiality: None
CVE-2021-47220 does not compromise confidentiality.
Integrity: None
CVE-2021-47220 does not impact data integrity.
Availability: None
CVE-2021-47220 does not affect system availability.

Exploit Prediction Scoring System (EPSS)

The EPSS score estimates the probability that this vulnerability will be exploited in the near future.

EPSS Score: 0.043% (probability of exploit)

EPSS Percentile: 11.87% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 88.13% of others.

CVE-2021-47220 References

External References

CWE Common Weakness Enumeration

Unknown

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CVE-2021-47220 Vulnerability Scoring