# CVE-2024-26990: KVM: x86/mmu: Write-protect L2 SPTEs in TDP MMU when clearing dirty status

> A flaw in Linux KVM TDP MMU allows L2 guests to bypass dirty logging, potentially leaking memory state to the host or other guests.

- **Severity:** High 8.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 May 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-26990, DEBIAN-CVE-2024-26990, GHSA-q5p9-3w3f-hr85, UBUNTU-CVE-2024-26990

## What is CVE-2024-26990?

CVE-2024-26990 is a high-severity vulnerability in Linux kernel, published on 1 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86/mmu: Write-protect L2 SPTEs in TDP MMU when clearing dirty status

Check kvm_mmu_page_ad_need_write_protect() when deciding whether to
write-protect or clear D-bits on TDP MMU SPTEs, so that the TDP MMU
accounts for any role-specific reasons for disabling D-bit dirty logging.

Specifically, TDP MMU SPTEs must be write-protected when the TDP MMU is
being used to run an L2 (i.e. L1 has disabled EPT) and PML is enabled.
KVM always disables PML when running L2, even when L1 and L2 GPAs are in
the some domain, so failing to write-protect TDP MMU SPTEs will cause
writes made by L2 to not be reflected in the dirty log.

[sean: massage shortlog and changelog, tweak ternary op formatting]

## Which versions are affected by CVE-2024-26990?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-26990?

Apply the vendor's patch.

## Is CVE-2024-26990 being exploited?

There is no known exploitation of CVE-2024-26990 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-26990 and fix it if it is affected.

What it is: CVE-2024-26990 is a high-severity vulnerability in Linux kernel, published on 1 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-26990 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2024-26990/ (Markdown: https://insights.sbomify.com/CVE-2024-26990/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-26990
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-26990
- OSV: https://osv.dev/vulnerability/CVE-2024-26990

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-26990/
Summaries are generated and may contain mistakes; the official description above is the record.