xen: x86 PV guests can free memory pages while still keeping a stale TLB entry pointing to them
CVE-2026-79603 is fixed in 15 products on 1 platform, first by SUSE-SU-2026:4090-1, released September 8, 2026. It is not reported as exploited. Patch Radar priority: Routine.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| xen · Debian 12.15 (bookworm) | 4.17.7+13-g2445b30a44-0+deb12u1 | DEBIAN-CVE-2026-79603 | Sep 8, 2026 |
| xen · Debian 13.5 (trixie) | 4.20.4+39-gf1e1321c87-0+deb13u1 | DEBIAN-CVE-2026-79603 | Sep 8, 2026 |
| xen · Debian 14 | 4.20.4+39-gf1e1321c87-1 | DEBIAN-CVE-2026-79603 | Sep 8, 2026 |
| xen · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen · sles 15.7 | 4.20.4_04-150700.3.46.1 | SUSE-SU-2026:4090-1 | Sep 8, 2026 |
| xen-debuginfo · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-debugsource · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-devel · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-doc · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-hypervisor · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-libs · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-libs-debuginfo · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-licenses · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-ocaml · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-ocaml-debuginfo · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-ocaml-devel · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-ocaml-devel-debuginfo · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-runtime · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
| xen-runtime-debuginfo · Fedora 43 | 4.20.4-2.fc43 | FEDORA-2026-A9EA805BC1 | Sep 17, 2026 |
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