CVE-2026-79603
MEDIUMDescription
x86 PV guests can free memory pages while still keeping a stale TLB entry pointing to them. A TLB flush is only issued by Xen (if needed) when the page is re-used. Since it's possible for the page to be scrubbed ahead of the TLB flush, there's a window where a PV guest can modify an already scrubbed page.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 13% of all known CVEs.
References
Related Vulnerabilities
Other CWE-664 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-27518 | Critical | 9.8 | 6.9% | KEV | Fix |
| CVE-2022-2048 | High | 7.5 | 2.6% | - | Fix |
| CVE-2022-2191 | High | 7.5 | 2.2% | - | - |
| CVE-2026-43503 | High | 7.0 | 2.0% | - | Fix |
| CVE-2020-3175 | High | 8.6 | 2.0% | - | - |
| CVE-2019-16779 | Medium | 5.8 | 1.7% | - | Fix |
Common questions
How do I fix CVE-2026-79603?
Upgrade xen on debian 13 to 4.20.4+39-gf1e1321c87-0+deb13u1 or later.
Is CVE-2026-79603 being actively exploited?
Not that we know of. CVE-2026-79603 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.22% is the estimated probability that it will be exploited in the next 30 days. That is higher than 13% of all scored CVEs.
How severe is CVE-2026-79603?
CVE-2026-79603 has a CVSS v3 base score of 4.3, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-79603 affect?
Published advisories record a fix for xen (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-79603
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-08.