Red Hat Enterprise Linux 8.2 update for kernel

1) Memory leak

EUVDB-ID: #VU55258

Risk: Low

CVSSv3.1: 4.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-25704

CWE-ID: CWE-401 - Missing release of memory after effective lifetime

Exploit availability: No

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to memory leak within the Linux kernel performance monitoring subsystem when using PERF_EVENT_IOC_SET_FILTER. A local user could use this flaw to starve the resources causing denial of service.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

kernel (Red Hat package): 4.18.0-193.6.3.el8_2 - 4.18.0-193.56.1.el8_2

Red Hat Enterprise Linux Server - TUS: 8.2

External links

http://access.redhat.com/errata/RHSA-2021:2718

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.

2) Protection Mechanism Failure

EUVDB-ID: #VU54455

Risk: Low

CVSSv3.1: 6.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

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

Install updates from vendor's website.

Vulnerable software versions

kernel (Red Hat package): 4.18.0-193.6.3.el8_2 - 4.18.0-193.56.1.el8_2

Red Hat Enterprise Linux Server - TUS: 8.2

External links

http://access.redhat.com/errata/RHSA-2021:2718

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) Improper Initialization

EUVDB-ID: #VU55259

Risk: Low

CVSSv3.1: 3.9 [CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-35508

CWE-ID: CWE-665 - Improper Initialization

Exploit availability: No

Description

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

The vulnerability exists due to improper initialization of the process id in the Linux kernel child/parent process identification handling while filtering signal handlers. A local user can run a specially crafted application to bypass checks to send any signal to a privileged process.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

kernel (Red Hat package): 4.18.0-193.6.3.el8_2 - 4.18.0-193.56.1.el8_2

Red Hat Enterprise Linux Server - TUS: 8.2

External links

http://access.redhat.com/errata/RHSA-2021:2718

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.

4) Use-after-free

EUVDB-ID: #VU54454

Risk: Low

CVSSv3.1: 6.1 [CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-33034

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

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

The vulnerability exists due to a use-after-free error in net/bluetooth/hci_event.c when destroying an hci_chan. A local user can escalate privileges on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

kernel (Red Hat package): 4.18.0-193.6.3.el8_2 - 4.18.0-193.56.1.el8_2

Red Hat Enterprise Linux Server - TUS: 8.2

External links

http://access.redhat.com/errata/RHSA-2021:2718

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) Integer overflow

EUVDB-ID: #VU55143

Risk: Low

CVSSv3.1: 7.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-33909

CWE-ID: CWE-190 - Integer overflow

Exploit availability: Yes

Description

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

The vulnerability exists due to integer overflow during size_t-to-int conversion when creating, mounting, and deleting a deep directory structure whose total path length exceeds 1GB. An unprivileged local user can write up to 10-byte string to an offset of exactly -2GB-10B below the beginning of a vmalloc()ated kernel buffer.

Successful exploitation of vulnerability may allow an attacker to exploit the our-of-bounds write vulnerability to execute arbitrary code with root privileges.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

kernel (Red Hat package): 4.18.0-193.6.3.el8_2 - 4.18.0-193.56.1.el8_2

Red Hat Enterprise Linux Server - TUS: 8.2

External links

http://access.redhat.com/errata/RHSA-2021:2718

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.