CVE-2026-63939 Detail
Received
This CVE record has recently been published to the CVE List and has been included within the NVD dataset. DescriptionIn the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Compute the correct max length of the in-GHCB scratch area When setting the length of the GHCB scratch area, and the area is in the GHCB shared buffer, set the effective length of the scratch area to the max possible size given the start of the guest-provided pointer, and the end of the shared buffer. The code was "fine" when first introduced, as KVM doesn't consult the length of the buffer when emulating MMIO, because the passed in @len always specifies the *max* size required. But for PSC requests, the incoming @len is just the minimum length (to process the header), and KVM needs to know the full size of the scratch area to avoid buffer overflows (spoiler alert). Opportunistically rename @len => @min_len to better reflect its role. Metrics
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CVSS 4.0 Severity and Vector Strings:
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Quick InfoCVE Dictionary Entry:CVE-2026-63939 NVD Published Date: 07/19/2026 NVD Last Modified: 07/20/2026 Source: kernel.org |
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