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VulnerabilityPublished Updated

CVE-2026-46113: Linux kernel · Use After Free

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.8 High · fixed in e9d4ea13aa2b6400bb10ec64b370ba3dadcd22f0 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in e9d4ea13aa2b6400bb10ec64b370ba3dadcd22f0, 9597963a8ca16259d194a1d9950d7bd22a10ab2f, 738ec97b1855df6c08fe2369f798fa0b972e556b +4
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 28 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 6aa8b732ca01c3d7a54e93f4d701b8aabbe60fb7, < e9d4ea13aa2b6400bb10ec64b370ba3dadcd22f0
Fixed in
  • e9d4ea13aa2b6400bb10ec64b370ba3dadcd22f0
LinuxLinuxAffected
  • ≥ 6aa8b732ca01c3d7a54e93f4d701b8aabbe60fb7, < 9597963a8ca16259d194a1d9950d7bd22a10ab2f
Fixed in
  • 9597963a8ca16259d194a1d9950d7bd22a10ab2f
LinuxLinuxAffected
  • ≥ 6aa8b732ca01c3d7a54e93f4d701b8aabbe60fb7, < 738ec97b1855df6c08fe2369f798fa0b972e556b
Fixed in
  • 738ec97b1855df6c08fe2369f798fa0b972e556b
LinuxLinuxAffected
  • ≥ 6aa8b732ca01c3d7a54e93f4d701b8aabbe60fb7, < 488e386484ec8c0e558be6e156edf34ed9f4d5c8
Fixed in
  • 488e386484ec8c0e558be6e156edf34ed9f4d5c8
LinuxLinuxAffected
  • ≥ 6aa8b732ca01c3d7a54e93f4d701b8aabbe60fb7, < 14d1e55dfd2cf4711bff164a6aaaddb783552134
Fixed in
  • 14d1e55dfd2cf4711bff164a6aaaddb783552134
LinuxLinuxAffected
  • ≥ 6aa8b732ca01c3d7a54e93f4d701b8aabbe60fb7, < 06c19c967b845b63172601fe459667d973b7e6b7
Fixed in
  • 06c19c967b845b63172601fe459667d973b7e6b7

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Fix shadow paging use-after-free due to unexpected GFN The shadow MMU computes GFNs for direct shadow pages using sp->gfn plus the SPTE index. This assumption breaks for shadow paging if the guest page tables are modified between VM entries (similar to commit aad885e77496, "KVM: x86/mmu: Drop/zap existing present SPTE even when creating an MMIO SPTE", 2026-03-27). The flow is as follows: - a PDE is installed for a 2MB mapping, and a page in that area is accessed. KVM creates a kvm_mmu_page consisting of 512 4KB pages; the kvm_mmu_page is marked by FNAME(fetch) as direct-mapped because the guest's mapping is a huge page (and thus contiguous). - the PDE mapping is changed from outside the guest. - the guest accesses another page in the same 2MB area. KVM installs a new leaf SPTE and rmap entry; the SPTE uses the "correct" GFN (i.e. based on the new mapping, as changed in the previous step) but that GFN is outside of the [sp->gfn, sp->gfn + 511] range; therefore the rmap entry cannot be found and removed when the kvm_mmu_page is zapped. - the memslot that covers the first 2MB mapping is deleted, and the kvm_mmu_page for the now-invalid GPA is zapped. However, rmap_remove() only looks at the [sp->gfn, sp->gfn + 511] range established in step 1, and fails to find the rmap entry that was recorded by step 3. - any operation that causes an rmap walk for the same page accessed by step 3 then walks a stale rmap and dereferences a freed kvm_mmu_page. This includes dirty logging or MMU notifier invalidations (e.g., from MADV_DONTNEED). The underlying issue is that KVM's walking of shadow PTEs assumes that if a SPTE is present when KVM wants to install a non-leaf SPTE, then the existing kvm_mmu_page must be for the correct gfn. Because the only way for the gfn to be wrong is if KVM messed up and failed to zap a SPTE... which shouldn't happen, but *actually* only happens in response to a guest write. That bug dates back literally forever, as even the first version of KVM assumes that the GFN matches and walks into the "wrong" shadow page. However, that was only an imprecision until 2032a93d66fa ("KVM: MMU: Don't allocate gfns page for direct mmu pages") came along. Fix it by checking for a target gfn mismatch and zapping the existing SPTE. That way the old SP and rmap entries are gone, KVM installs the rmap in the right location, and everyone is happy.

References

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