PT-2021-8182 · Linux+3 · Linux Kernel+3
Sean Christopherson
·
Published
2021-11-15
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Updated
2025-01-14
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CVE-2021-47217
CVSS v3.1
5.5
Medium
| Vector | AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Name of the Vulnerable Software and Affected Versions
Linux kernel versions prior to 5.15.0-rc2+
Description
The vulnerability is related to a NULL pointer dereference in the
set hv tscchange cb() function when setting Hyper-V's TSC change callback. If Hyper-V setup fails, the kernel will still report that it's running under Hyper-V, but will have silently disabled nearly all functionality. This can lead to a denial of service. The issue is caused by a kernel NULL pointer dereference, which occurs when the hv vp index array is not checked for validity before being dereferenced.Recommendations
To resolve the issue, update the Linux kernel to a version that includes the fix for the NULL pointer dereference in
set hv tscchange cb(). As a temporary workaround, consider disabling the set hv tscchange cb() function until a patch is available. However, this may have unintended consequences and should be done with caution.
At the moment, there is no information about a newer version that contains a fix for this vulnerability.Exploit
NULL Pointer Dereference
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Weakness Enumeration
Related Identifiers
Affected Products
Astra Linux
Linux Kernel
Red Os
Suse