CVE-2021-47255
What it is
In the Linux kernel, the following vulnerability has been resolved: kvm: LAPIC: Restore guard to prevent illegal APIC register access Per the SDM, "any access that touches bytes 4 through 15 of an APIC register may cause undefined behavior and must not be executed." Worse, such an access in kvm_lapic_reg_read can result in a leak of kernel stack contents. Prior to commit 01402cf81051 ("kvm: LAPIC: write down valid APIC registers"), such an access was explicitly disallowed. Restore the guard that was removed in that commit.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, 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: 7.1 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Record status
- Analyzed
Affected
- Linux Kernel < 5.4.128
- Linux Kernel < 5.10.46
- Linux Kernel < 5.12.13
- Linux Kernel 5.13
Attack profile CVSS 3.1 · 7.1
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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-2021-47255.md and follow it. Check whether this project is affected by CVE-2021-47255. 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/018685461a5b9a9a70e664ac77aef0d7415a3fd5
- https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6
- https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210
- https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84
- https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5
- https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6
- https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210
- https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84
References
- https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5
- https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6
- https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210
- https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84
- https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5
- https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6
- https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210
- https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84