CVE-2024-35804
What it is
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Mark target gfn of emulated atomic instruction as dirty When emulating an atomic access on behalf of the guest, mark the target gfn dirty if the CMPXCHG by KVM is attempted and doesn't fault. This fixes a bug where KVM effectively corrupts guest memory during live migration by writing to guest memory without informing userspace that the page is dirty. Marking the page dirty got unintentionally dropped when KVM's emulated CMPXCHG was converted to do a user access. Before that, KVM explicitly mapped the guest page into kernel memory, and marked the page dirty during the unmap phase. Mark the page dirty even if the CMPXCHG fails, as the old data is written back on failure, i.e. the page is still written. The value written is guaranteed to be the same because the operation is atomic, but KVM's ABI is that all writes are dirty logged regardless of the value written. And more importantly, that's what KVM did before the buggy commit. Huge kudos to the folks on the Cc list (and many others), who did all the actual work of triaging and debugging. base-commit: 6769ea8da8a93ed4630f1ce64df6aafcaabfce64
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 8.8 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Weakness
- CWE-401
- Record status
- Modified
Affected
- Linux Kernel < 5.15.154
- Linux Kernel < 5.18
- Linux Kernel < 6.1.84
- Linux Kernel < 6.6.24
- Linux Kernel < 6.7.12
- Linux Kernel 6.8
Attack profile CVSS 3.1 · 8.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2024-35804.md and follow it. Check whether this project is affected by CVE-2024-35804. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/225d587a073584946c05c9b7651d637bd45c0c71
- https://git.kernel.org/stable/c/726374dde5d608b15b9756bd52b6fc283fda7a06
- https://git.kernel.org/stable/c/910c57dfa4d113aae6571c2a8b9ae8c430975902
- https://git.kernel.org/stable/c/9d1b22e573a3789ed1f32033ee709106993ba551
- https://git.kernel.org/stable/c/a9bd6bb6f02bf7132c1ab192ba62bbfa52df7d66
- https://git.kernel.org/stable/c/225d587a073584946c05c9b7651d637bd45c0c71
- https://git.kernel.org/stable/c/726374dde5d608b15b9756bd52b6fc283fda7a06
- https://git.kernel.org/stable/c/910c57dfa4d113aae6571c2a8b9ae8c430975902
- https://git.kernel.org/stable/c/9d1b22e573a3789ed1f32033ee709106993ba551
- https://git.kernel.org/stable/c/a9bd6bb6f02bf7132c1ab192ba62bbfa52df7d66
References
- https://git.kernel.org/stable/c/225d587a073584946c05c9b7651d637bd45c0c71
- https://git.kernel.org/stable/c/726374dde5d608b15b9756bd52b6fc283fda7a06
- https://git.kernel.org/stable/c/910c57dfa4d113aae6571c2a8b9ae8c430975902
- https://git.kernel.org/stable/c/9d1b22e573a3789ed1f32033ee709106993ba551
- https://git.kernel.org/stable/c/a9bd6bb6f02bf7132c1ab192ba62bbfa52df7d66
- https://git.kernel.org/stable/c/225d587a073584946c05c9b7651d637bd45c0c71
- https://git.kernel.org/stable/c/726374dde5d608b15b9756bd52b6fc283fda7a06
- https://git.kernel.org/stable/c/910c57dfa4d113aae6571c2a8b9ae8c430975902
- https://git.kernel.org/stable/c/9d1b22e573a3789ed1f32033ee709106993ba551
- https://git.kernel.org/stable/c/a9bd6bb6f02bf7132c1ab192ba62bbfa52df7d66