CVE-2025-37816: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-37816 is a vulnerability discovered in the Linux kernel's mei:vsc component, specifically related to an invalid use of the counted_by() attribute. The issue was disclosed on May 8, 2025, affecting various Linux distributions including Ubuntu and Debian systems (NVD, Wiz).

The vulnerability stems from an incorrect implementation where gcc 15 honors the _countedby(len) attribute on vsctppacket.buf[], but the code uses it incorrectly. The len parameter contains the actual packet length without the CRC rather than the available buffer size. This leads to a buffer overflow condition when vsctpxfer() attempts to add the CRC to buf[], triggering a fortify-panic handler due to a 4-byte write attempt to a buffer of size 0 (NVD, Wiz).

When exploited, this vulnerability can result in buffer overflow conditions in the Linux kernel's mei:vsc component. The immediate impact is a system panic when the fortify handler detects the overflow attempt, which could potentially lead to system instability or denial of service (Wiz).

A fix has been implemented by restructuring the vsctppacket struct definition. Instead of simply removing the counted-by attribute, the solution involves splitting the struct into a header and a full-packet definition, using a fixed size buf[] in the packet definition. This approach maintains the effectiveness of fortify-source buffer overrun checking while correctly handling the buffer size (NVD, Wiz).