CVE-2026-63899: Linux kernel · USB: serial: mxuport: fix memory corruption with small endpoint
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 30 Oct 2026, 15:35 UTC
Rated High by Threat Radar's AI analysis · No CVSS score from NVD or the CNA
Thin evidence
One scorer or noneExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
AI-suggested
A fix has been implemented in the Linux kernel to enforce a minimum bulk-out endpoint max packet size of eight bytes in the mxuport driver. Users should update to a Linux kernel version that includes this fix once it is released. No additional mitigation steps are indicated.
Description
A memory corruption vulnerability in the Linux kernel's USB serial mxuport driver was fixed. The issue involved improper handling of bulk-out endpoint max packet sizes smaller than eight bytes, which could lead to user-controlled slab corruption if a malicious device reported a smaller size.
References
- git.kernel.org/stable/c/086b858b5f5125bc9d967ea2bd825f83d9f8f29d (opens in a new tab)
- git.kernel.org/stable/c/2f3661eb2446e1ef593da45e01a3b21a906768ec (opens in a new tab)
- git.kernel.org/stable/c/ccbec56f2f9af008f1574335cc6a668f16603e47 (opens in a new tab)
- git.kernel.org/stable/c/be3a1ed4ae51fa8dde57383277d336ce834f2cd9 (opens in a new tab)
- git.kernel.org/stable/c/e906545641d34fb1a09a65b4b5cfdff40eb09681 (opens in a new tab)
- git.kernel.org/stable/c/6c0cf56f00f280d72180bb6ce79741bc787a6269 (opens in a new tab)
- git.kernel.org/stable/c/b40166b4ef96067620a0f248e74ad9658c8f680c (opens in a new tab)
- git.kernel.org/stable/c/4085f0dbb1ce2251c9a5938d693de6593f0ab2bd (opens in a new tab)