PT-2024-11398 · Linux+2 · Linux Kernel+2
Vlad Buslov
·
Published
2021-09-30
·
Updated
2025-01-27
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CVE-2021-47402
CVSS v3.1
7.8
High
| Vector | AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 use-after-free issue in the
fl walk function of the Linux kernel's cls flower module. This issue occurs when a filter is deleted concurrently while the fl walk function is iterating over it, causing a use-after-free error. The vulnerability can be exploited by an attacker to potentially execute arbitrary code or cause a denial-of-service condition.The
fl walk function has been refactored to use idr for each entry continue ul and to obtain an RCU read lock while iterating over the filters, which should prevent the use-after-free issue. The vulnerability has been identified through a KASAN (Kernel Address Sanitizer) trace.Recommendations
To resolve this issue, update the Linux kernel to a version that includes the fix for this vulnerability. Specifically, update to a version later than 5.15.0-rc2+.
As a temporary workaround, consider disabling the
fl walk function until a patch is available. However, this may have unintended consequences and should be carefully evaluated before implementation.Note: The provided information does not specify the exact version that includes the fix, so it is recommended to update to the latest available version of the Linux kernel.
Fix
Use After Free
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Weakness Enumeration
Related Identifiers
Affected Products
Astra Linux
Linux Kernel
Suse