CVE-2021-47267
What it is
In the Linux kernel, the following vulnerability has been resolved: usb: fix various gadget panics on 10gbps cabling usb_assign_descriptors() is called with 5 parameters, the last 4 of which are the usb_descriptor_header for: full-speed (USB1.1 - 12Mbps [including USB1.0 low-speed @ 1.5Mbps), high-speed (USB2.0 - 480Mbps), super-speed (USB3.0 - 5Gbps), super-speed-plus (USB3.1 - 10Gbps). The differences between full/high/super-speed descriptors are usually substantial (due to changes in the maximum usb block size from 64 to 512 to 1024 bytes and other differences in the specs), while the difference between 5 and 10Gbps descriptors may be as little as nothing (in many cases the same tuning is simply good enough). However if a gadget driver calls usb_assign_descriptors() with a NULL descriptor for super-speed-plus and is then used on a max 10gbps configuration, the kernel will crash with a null pointer dereference, when a 10gbps capable device port + cable + host port combination shows up. (This wouldn't happen if the gadget max-speed was set to 5gbps, but it of course defaults to the maximum, and there's no real reason to artificially limit it) The fix is to simply use the 5gbps descriptor as the 10gbps descriptor, if a 10gbps descriptor wasn't provided. Obviously this won't fix the problem if the 5gbps descriptor is also NULL, but such cases can't be so trivially solved (and any such gadgets are unlikely to be used with USB3 ports any way).
At a glance
- Exploitability
- Can be exploited over the network with a low-privilege account. Limited direct impact.
- Exploit odds
- 0.7% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.7% in the next 30 days (EPSS).
- Severity: 6.3 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.7% · EPSS, next 30 days
- Weakness
- CWE-476 · NULL pointer dereference
- Record status
- Analyzed
Affected
- Linux Kernel < 4.9.273
- Linux Kernel < 4.14.237
- Linux Kernel < 4.19.195
- Linux Kernel < 5.4.126
- Linux Kernel < 5.10.44
- Linux Kernel < 5.12.11
- Linux Kernel 5.13
Attack profile CVSS 3.1 · 6.3
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-47267.md and follow it. Check whether this project is affected by CVE-2021-47267. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/032e288097a553db5653af552dd8035cd2a0ba96
- https://git.kernel.org/stable/c/45f9a2fe737dc0a5df270787f2231aee8985cd59
- https://git.kernel.org/stable/c/5ef23506695b01d5d56a13a092a97f2478069d75
- https://git.kernel.org/stable/c/70cd19cb5bd94bbb5bacfc9c1e4ee0071699a604
- https://git.kernel.org/stable/c/b972eff874637402ddc4a7dd11fb22538a0b6d28
- https://git.kernel.org/stable/c/ca6bc277430d90375452b60b047763a090b7673e
- https://git.kernel.org/stable/c/fd24be23abf3e94260be0f00bb42c7e91d495f87
- https://git.kernel.org/stable/c/032e288097a553db5653af552dd8035cd2a0ba96
- https://git.kernel.org/stable/c/45f9a2fe737dc0a5df270787f2231aee8985cd59
- https://git.kernel.org/stable/c/5ef23506695b01d5d56a13a092a97f2478069d75
References
- https://git.kernel.org/stable/c/032e288097a553db5653af552dd8035cd2a0ba96
- https://git.kernel.org/stable/c/45f9a2fe737dc0a5df270787f2231aee8985cd59
- https://git.kernel.org/stable/c/5ef23506695b01d5d56a13a092a97f2478069d75
- https://git.kernel.org/stable/c/70cd19cb5bd94bbb5bacfc9c1e4ee0071699a604
- https://git.kernel.org/stable/c/b972eff874637402ddc4a7dd11fb22538a0b6d28
- https://git.kernel.org/stable/c/ca6bc277430d90375452b60b047763a090b7673e
- https://git.kernel.org/stable/c/fd24be23abf3e94260be0f00bb42c7e91d495f87
- https://git.kernel.org/stable/c/032e288097a553db5653af552dd8035cd2a0ba96
- https://git.kernel.org/stable/c/45f9a2fe737dc0a5df270787f2231aee8985cd59
- https://git.kernel.org/stable/c/5ef23506695b01d5d56a13a092a97f2478069d75
- https://git.kernel.org/stable/c/70cd19cb5bd94bbb5bacfc9c1e4ee0071699a604
- https://git.kernel.org/stable/c/b972eff874637402ddc4a7dd11fb22538a0b6d28
- https://git.kernel.org/stable/c/ca6bc277430d90375452b60b047763a090b7673e
- https://git.kernel.org/stable/c/fd24be23abf3e94260be0f00bb42c7e91d495f87