Xen Grant Table V1/V2 Switch CVE-2026-62435: Locked State Assumption
CVE-2026-62435 Published on July 28, 2026
grant-table: version change racing with other operations
[This CNA information record relates to multiple CVEs; the
text explains which aspects/vulnerabilities correspond to which CVE.]
With the introduction of Grant Table v2 came the requirement to be able to
switch between versions. Switching from v1 to v2 reduces the number of
valid grant references, as a bigger shared entry structure is then needed
while the shared table doesn't change size. Switching from v2 back to v1
the status frames, which are separate in v2, go away.
Code holding, but intermediately dropping and then re-acquiring the grant
table lock, sometimes wrongly assumes that said properties wouldn't change
across the window in time where the lock is not being held.
The v1 -> v2 issue is CVE-2026-62435.
The v2 -> v1 issue is CVE-2026-62436.
Vulnerability Analysis
CVE-2026-62435 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality, a small impact on integrity, and a small impact on availability.
Weakness Type
What is a Race Condition Vulnerability?
The program contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently.
CVE-2026-62435 has been classified to as a Race Condition vulnerability or weakness.
Products Associated with CVE-2026-62435
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