Linux Kernel up to 4.14.90/4.19.12 KVM Hypervisor nested_get_vmcs12_pages use after free

CVSS Meta Temp Score
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7.0$0-$5k0.00

A vulnerability classified as critical was found in Linux Kernel up to 4.14.90/4.19.12 (Operating System). Affected by this vulnerability is the function nested_get_vmcs12_pages of the component KVM Hypervisor. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

A use-after-free issue was found in the way the Linux kernel's KVM hypervisor processed posted interrupts when nested(=1) virtualization is enabled. In nested_get_vmcs12_pages(), in case of an error while processing posted interrupt address, it unmaps the 'pi_desc_page' without resetting 'pi_desc' descriptor address, which is later used in pi_test_and_clear_on(). A guest user/process could use this flaw to crash the host kernel resulting in DoS or potentially gain privileged access to a system. Kernel versions before 4.14.91 and before 4.19.13 are vulnerable.

The bug was discovered 12/18/2018. The weakness was published 01/03/2019 as confirmed bug report (Bugzilla). The advisory is shared at bugzilla.redhat.com. This vulnerability is known as CVE-2018-16882 since 09/11/2018. The exploitation appears to be easy. An attack has to be approached locally. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available.

The vulnerability was handled as a non-public zero-day exploit for at least 16 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 121470 (Ubuntu 18.04 LTS : linux-hwe vulnerabilities (USN-3872-1)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Ubuntu Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 197355 (Ubuntu Security Notification for Linux-hwe Vulnerabilities (USN-3872-1)).

Upgrading to version 4.14.91, 4.14.90 or 4.19.13 eliminates this vulnerability. A possible mitigation has been published 4 weeks after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (121470). Similar entries are available at 122170 and 130426.

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CPE 2.3info

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CVSSv4info

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CVSSv3info

VulDB Meta Base Score: 7.1
VulDB Meta Temp Score: 7.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 8.8
NVD Vector: 🔍

CNA Base Score: 6.1
CNA Vector (Red Hat, Inc.): 🔍

CVSSv2info

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VulDB Base Score: 🔍
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Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
ATT&CK: Unknown

Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
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Nessus ID: 121470
Nessus Name: Ubuntu 18.04 LTS : linux-hwe vulnerabilities (USN-3872-1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Upgrade: Kernel 4.14.91/4.14.90/4.19.13

Timelineinfo

09/11/2018 🔍
12/18/2018 +98 days 🔍
12/18/2018 +0 days 🔍
01/03/2019 +16 days 🔍
01/03/2019 +0 days 🔍
01/04/2019 +1 days 🔍
01/29/2019 +25 days 🔍
01/30/2019 +1 days 🔍
06/23/2023 +1605 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: USN-3872-1
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2018-16882 (🔍)
SecurityFocus: 106254 - Linux Kernel CVE-2018-16882 Local Denial of Service Vulnerability

See also: 🔍

Entryinfo

Created: 01/04/2019 12:17
Updated: 06/23/2023 07:26
Changes: 01/04/2019 12:17 (75), 04/25/2020 21:21 (10), 06/23/2023 07:15 (4), 06/23/2023 07:20 (13), 06/23/2023 07:26 (1)
Complete: 🔍

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