CVE-2026-93186
In the Linux kernel, the following vulnerability has been resolved: cxl/mbox: Clamp mailbox output allocation to the payload size CXL_MEM_SEND_COMMAND bounds the user's in.size to the mailbox payload size but leaves out.size unbounded, then cxl_mbox_cmd_ctor() calls kvzalloc(out.size). A large out.size drives a huge allocation, above INT_MAX it WARNs and taints, and with panic_on_warn=1 it panics. The transport __cxl_pci_mbox_send_cmd() already clamps the response copy to min(out.size, payload_size, device len), so the output buffer is never written beyond payload_size. Clamp the allocation to payload_size too, matching the RAW path.
Affected versions
Linux kernel versions
5.12
and later are affected. Fixed in
6.12.110,
6.18.52,
7.2.6,
7.3-rc1
and their respective stable series.
References
4 totalFrequently asked questions
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What is CVE-2026-93186?
CVE-2026-93186 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.12 onward and has been patched in 6.12.110, 6.18.52, 7.2.6 and others. CVE-2026-93186 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-93186?
Yes. CVE-2026-93186 has been patched. Fixed versions include 6.12.110, 6.18.52, 7.2.6 and others. If you are running Linux kernel 5.12 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-93186 actively exploited?
No. CVE-2026-93186 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.