CVE-2026-93186cxl/mbox: Clamp mailbox output allocation to the payload size
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 19, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 before f5d2bbf0300f46307948864fbb97bce5097f4fe2; 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 builds before 31d4841eca7c4b75751ca96d24339e19303337f2; from 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 before b4e11c731d6bee3b87315e055a1ca417c92dc1fc; 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 builds before 8a13db9f899d149c3aab24abcb668121cfda5a4f | CNA record |
References
- https://git.kernel.org/stable/c/f5d2bbf0300f46307948864fbb97bce5097f4fe2
- https://git.kernel.org/stable/c/31d4841eca7c4b75751ca96d24339e19303337f2
- https://git.kernel.org/stable/c/b4e11c731d6bee3b87315e055a1ca417c92dc1fc
- https://git.kernel.org/stable/c/8a13db9f899d149c3aab24abcb668121cfda5a4f
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.