CVE-2026-63937: high-severity vulnerability in Linux
KVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer
Published · Updated
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.8epss 0.1%
exploitation probability
0.1%top 97% of all CVEs
observed exploitation
nono source reports it
In the Linux kernel, the following vulnerability has been resolved:
KVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer
Use READ_ONCE() when reading entries/indices from the guest-accessible
Page State Change buffer to defend against TOCTOU bugs.
Don't bother with READ_ONCE()/WRITE_ONCE() for cases where KVM is writing
(and not consuming the result!), as the guest isn't supposed to touch the
buffer while it's being processed. I.e. using READ_ONCE() is all about
protecting against misbehaving guests.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Affected products
Linux · LinuxRelated CVEs — Linux
In the same product, most dangerous first.
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