PT-2025-8306 · Linux+4 · Linux Kernel+4
Laurent Fasnacht
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Published
2022-05-31
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Updated
2025-09-29
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CVE-2022-49372
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 5.16.12-1~bpo11+1
Description
A vulnerability in the Linux kernel has been resolved. The issue occurs when a new passive FastOpen TCP socket is created and a socket operation goes through a specific sequence of events, ultimately leading to the
tcp rtx synack() function being called in process context. This is a problem because tcp rtx synack() was previously always called from a BH handler, from a timer handler, and not from a preemptible context. The vulnerability can be triggered when the kernel is built with CONFIG DEBUG PREEMPT=y. The estimated number of potentially affected devices is not specified.Recommendations
For Linux kernel versions prior to 5.16.12-1~bpo11+1, update to a newer version that includes the fix, which uses
TCP INC STATS() and NET INC STATS() to avoid assuming the caller is in a non-preemptible context. As a temporary workaround, consider disabling the tcp rtx synack() function until a patch is available. However, this is not a recommended long-term solution, and updating to a fixed version is the preferred resolution.Exploit
Fix
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Weakness Enumeration
Related Identifiers
Affected Products
Astra Linux
Centos
Linux Kernel
Red Hat
Suse