In the Linux kernel, the following vulnerability has been resolved: USB: serial: mct_u232: fix memory corruption with small endpoint The driver… (CVE-2026-63898)
A vulnerability in the Linux kernel's USB serial driver mct_u232 was fixed to prevent memory corruption caused by a device reporting a smaller maximum packet size than expected. The driver previously increased the maximum transfer size for a device that only accepts 16-byte packets on a 32-byte bulk-out endpoint, which could lead to slab corruption. The fix ensures the maximum transfer size is never increased beyond the device's actual endpoint size.
AI Analysis
Technical Summary
The Linux kernel's USB serial driver mct_u232 had a vulnerability where it incorrectly overrode the maximum transfer size for a device with a 32-byte bulk-out endpoint that only accepts 16-byte packets. This mismatch could cause memory corruption (slab corruption) if a malicious device reported a smaller endpoint max packet size than expected. The vulnerability was resolved by ensuring the driver does not increase the maximum transfer size beyond the device's actual endpoint size, preventing potential memory corruption.
Potential Impact
The vulnerability could lead to memory corruption within the kernel's USB serial driver when interacting with a malicious USB device that reports a smaller maximum packet size than expected. This could potentially destabilize the kernel or cause other unintended behavior. No known exploits in the wild have been reported.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to prevent this memory corruption issue by ensuring the maximum transfer size is not increased beyond the device's reported endpoint size. Users should update to the fixed kernel version once available. Patch status is not explicitly confirmed in the provided data; check the official Linux kernel advisories for the exact fixed versions and apply updates accordingly.
In the Linux kernel, the following vulnerability has been resolved: USB: serial: mct_u232: fix memory corruption with small endpoint The driver… (CVE-2026-63898)
Description
A vulnerability in the Linux kernel's USB serial driver mct_u232 was fixed to prevent memory corruption caused by a device reporting a smaller maximum packet size than expected. The driver previously increased the maximum transfer size for a device that only accepts 16-byte packets on a 32-byte bulk-out endpoint, which could lead to slab corruption. The fix ensures the maximum transfer size is never increased beyond the device's actual endpoint size.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel's USB serial driver mct_u232 had a vulnerability where it incorrectly overrode the maximum transfer size for a device with a 32-byte bulk-out endpoint that only accepts 16-byte packets. This mismatch could cause memory corruption (slab corruption) if a malicious device reported a smaller endpoint max packet size than expected. The vulnerability was resolved by ensuring the driver does not increase the maximum transfer size beyond the device's actual endpoint size, preventing potential memory corruption.
Potential Impact
The vulnerability could lead to memory corruption within the kernel's USB serial driver when interacting with a malicious USB device that reports a smaller maximum packet size than expected. This could potentially destabilize the kernel or cause other unintended behavior. No known exploits in the wild have been reported.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to prevent this memory corruption issue by ensuring the maximum transfer size is not increased beyond the device's reported endpoint size. Users should update to the fixed kernel version once available. Patch status is not explicitly confirmed in the provided data; check the official Linux kernel advisories for the exact fixed versions and apply updates accordingly.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-6rff-3vpp-qcmx
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-63898"]
- Ecosystems
- []
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a5d27ab2a4a8d598912f92f
Added to database: 07/19/2026, 19:38:19 UTC
Last enriched: 07/19/2026, 20:10:15 UTC
Last updated: 07/20/2026, 17:26:47 UTC
Views: 12
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