What is CVE-2026-53359?
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Fix shadow paging use-after-free due to unexpected role Commit 0cb2af2ea66ad ("KVM: x86: Fix shadow paging use-after-free due to unexpected GFN") fixed a shadow paging mismatch between stored and computed GFNs; the bug could be triggered by changing a PDE mapping from outside the guest, and then deleting a memslot. The rmap_remove() call would miss entries created after the PDE change because the GFN of the leaf SPTE does not match the GFN of the struct kvm_mmu_page. A similar hole however remains if the modified PDE points to a non-leaf page. In this case the gfn can be made to match, but the role does not match: the original large 2MB page creates a kvm_mmu_page with direct=1, while the new 4KB needs a kvm_mmu_page with direct=0. However, kvm_mmu_get_child_sp() does not compare the role, and therefore reuses the page. The next step is installing a leaf (4KB) SPTE on the new path which records an rmap entry under the gfn resolved by the walk. But when that child is zapped its parent kvm_mmu_page has direct=1 and kvm_mmu_page_get_gfn() computes the gfn for the 4KB page as sp->gfn + index instead of using sp->shadowed_translation[] (or sp->gfns[] in older kernels). It therefore fails to remove the recorded entry. When the memslot is dropped the shadow page is freed but the rmap entry survives, as in the scenario that was already fixed. Code that later walks that gfn (dirty logging, MMU notifier invalidation, and so on) dereferences an sptep that lies in the freed page, causing the use-after-free.
The record classifies CVE-2026-53359 under weakness class CWE-416. Its CVSS v3 base vector states that the flaw requires local access to the host, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 116 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 8.8 — HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - EPSS (FIRST)
- 0.9% probability of exploitation in the next 30 days, higher than 61.0% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 8.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-07-04, last modified 2026-10-03
Is CVE-2026-53359 being exploited?
Weaponised exploit code for CVE-2026-53359 is publicly available. 8 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 34 in the Threadlinqs vulnerability feed.
- Aoripus-LTD/Januscape-Hotfix (github)
- 0xBlackash/CVE-2026-53359 (github)
- chuzhongyun/CVE-2026-53359-Kernel-Fix (github)
- xj2268-TA/KVM-Januscape (github)
- HORKimhab/CVE-2026-53359 (github)
- suominen/januscape (github)
- ndouglas-cloudsmith/CVE-2026-53359 (github)
- trickest/cve (trickest)
Affected products and versions
- Linux: Linux
How to fix CVE-2026-53359
No vendor patch reference has been recorded for CVE-2026-53359 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-53359
1 tracked threat in the Threadlinqs corpus references CVE-2026-53359, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, FIRST EPSS, public proof-of-concept repositories. Last verified by Threadlinqs on .
Other references
- git.kernel.org
- git.kernel.org (b1337aae5e194324e4810d561764e7793f8b3864)
- git.kernel.org (9291654d69e08542de37755cebe4d5b02c3170d1)
- git.kernel.org (2ad3afa40ac6aa340dada122f9abfa46c0a6eb35)
- git.kernel.org (5e470998a23e4c3d89ed24e8172cb22747e61efa)
Showing 5 of 7 recorded references.