Ubuntu update for linux-oem-5.10

Published: 2021-10-06

Risk	Low
Patch available	YES
Number of vulnerabilities	5
CVE-ID	CVE-2021-41073 CVE-2020-26541 CVE-2021-22543 CVE-2021-3612 CVE-2021-38199
CWE-ID	CWE-269 CWE-693 CWE-119 CWE-787 CWE-362
Exploitation vector	Local network
Public exploit	Public exploit code for vulnerability #1 is available. Public exploit code for vulnerability #3 is available.
Vulnerable software	Ubuntu Operating systems & Components / Operating system linux-image-oem-20.04b (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.10.0-1049-oem (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-oem-20.04 (Ubuntu package) Operating systems & Components / Operating system package or component
Vendor	Canonical Ltd.

Security Bulletin

This security bulletin contains information about 5 vulnerabilities.

1) Improper Privilege Management

EUVDB-ID: #VU68300

Risk: Low

CVSSv4.0: 7.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2021-41073

CWE-ID: CWE-269 - Improper Privilege Management

Exploit availability: Yes

Description

The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to improper privilege management within the loop_rw_iter() function in fs/io_uring.c in Linux kernel. A local user can escalate privileges on the system by using IORING_OP_PROVIDE_BUFFERS to trigger a free of a kernel buffer.

Mitigation

Update the affected package linux-oem-5.10 to the latest version.

Vulnerable software versions

Ubuntu: 20.04

linux-image-oem-20.04b (Ubuntu package): before 5.10.0.1049.51

linux-image-5.10.0-1049-oem (Ubuntu package): before 5.10.0-1049.51

linux-image-oem-20.04 (Ubuntu package): before 5.10.0.1049.51

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5106-1

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

2) Protection Mechanism Failure

EUVDB-ID: #VU54455

Risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-26541

CWE-ID: CWE-693 - Protection Mechanism Failure

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism. This affects certs/blacklist.c and certs/system_keyring.c. A local user can escalate privileges on the system.

Mitigation

Update the affected package linux-oem-5.10 to the latest version.

Vulnerable software versions

Ubuntu: 20.04

linux-image-oem-20.04b (Ubuntu package): before 5.10.0.1049.51

linux-image-5.10.0-1049-oem (Ubuntu package): before 5.10.0-1049.51

linux-image-oem-20.04 (Ubuntu package): before 5.10.0.1049.51

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5106-1

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Buffer overflow

EUVDB-ID: #VU56018

Risk: Low

CVSSv4.0: 7.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2021-22543

CWE-ID: CWE-119 - Memory corruption

Exploit availability: Yes

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a boundary error in Linux kernel when handling VM_IO|VM_PFNMAP vmas in KVM. A local user can can bypass RO checks and cause the pages to get freed while still accessible by the VMM and guest. As a result, an attacker with the ability to start and control a VM to read/write random pages of memory, can trigger memory corruption and execute arbitrary code with elevated privileges.

Mitigation

Update the affected package linux-oem-5.10 to the latest version.

Vulnerable software versions

Ubuntu: 20.04

linux-image-oem-20.04b (Ubuntu package): before 5.10.0.1049.51

linux-image-5.10.0-1049-oem (Ubuntu package): before 5.10.0-1049.51

linux-image-oem-20.04 (Ubuntu package): before 5.10.0.1049.51

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5106-1

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

4) Out-of-bounds write

EUVDB-ID: #VU55231

Risk: Low

CVSSv4.0: 4.4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-3612

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a boundary error in joystick devices subsystem in Linux kernel. A local user can make a specially crafted JSIOCSBTNMAP IOCTL call, trigger out-of-bounds write and execute arbitrary code with escalated privileges.

Mitigation

Update the affected package linux-oem-5.10 to the latest version.

Vulnerable software versions

Ubuntu: 20.04

linux-image-oem-20.04b (Ubuntu package): before 5.10.0.1049.51

linux-image-5.10.0-1049-oem (Ubuntu package): before 5.10.0-1049.51

linux-image-oem-20.04 (Ubuntu package): before 5.10.0.1049.51

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5106-1

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

5) Race condition

EUVDB-ID: #VU61208

Risk: Low

CVSSv4.0: 1.3 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-38199

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to fs/nfs/nfs4client.c in the Linux kernel has incorrect connection-setup ordering. A remote attacker with access to a remote NFSv4 server can perform a denial of service (DoS) attack by arranging the server to be unreachable during trunking detection.

Mitigation

Update the affected package linux-oem-5.10 to the latest version.

Vulnerable software versions

Ubuntu: 20.04

linux-image-oem-20.04b (Ubuntu package): before 5.10.0.1049.51

linux-image-5.10.0-1049-oem (Ubuntu package): before 5.10.0-1049.51

linux-image-oem-20.04 (Ubuntu package): before 5.10.0.1049.51

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5106-1

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.