CVE-2026-79610: grant-table: double version change race

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.1%

EPSS score, percentile 3.9 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

8.8 High

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Workaround (from the CVE record)

Using the "gnttab=max-ver:1" hypervisor command line option will avoid the vulnerability. Using the "max_grant_version=1" guest configuration option for guests will also avoid the vulnerability.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Versions not listed are: unknown.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

XSA-501 was about issues with v1 -> v2 and v2 -> v1 changes racing certain other grant table operations. Sadly a v2 -> v1 -> v2 change has yet another effect which wasn't accounted for: During the first change, status pages would be freed. During the second change they would be allocated again. Hence across the full pair of change the addresses of the status pages may change, rendering stale p…

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-79610 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 13 Oct 2026.
• The CVE record carries a CVSS v3.1 base score of 8.8 (High), taken from CISA's enrichment of the record.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.1% (percentile 3.9), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact total.
• The credits in the CVE record name Anthropic (Claude) as finder.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

grant-table: double version change race

XSA-501 was about issues with v1 -> v2 and v2 -> v1 changes racing certain other grant table operations. Sadly a v2 -> v1 -> v2 change has yet another effect which wasn't accounted for: During the first change, status pages would be freed. During the second change they would be allocated again. Hence across the full pair of change the addresses of the status pages may change, rendering stale previously calculated pointers into the status array.

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline