hv_netvsc: Don't free decrypted memory
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Fix
- Fixed in 6.6.31, 6.8.10
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
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.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original 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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- Linux Linux
Version range not reported
- Linux Linux
5.16
- KernelLinux
From 5.16.0 · fixed in 6.6.31; From 6.7.0 · fixed in 6.8.10
References 4
Questions about CVE-2024-36911
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: git.kernel.org
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: git.kernel.org
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: git.kernel.org
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: cve.now feed data