1) Use-after-free

EUVDB-ID: #VU56393

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-2021-3715

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 the "Routing decision" classifier in the Linux kernel's Traffic Control networking subsystem (route4_change() function in net/sched/cls_route.c) in the way it handled changing of classification filters. A local user can trigger a use-after-free error and execute arbitrary code with elevated privileges.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

kernel (Red Hat package): 3.10.0-123.1.2.el7 - 3.10.0-1160.41.1.el7

Red Hat Enterprise Linux for Power, little endian: 7

Red Hat Enterprise Linux for Power, big endian: 7

Red Hat Enterprise Linux for IBM z Systems: 7

Red Hat Enterprise Linux for Scientific Computing: 7

Red Hat Enterprise Linux Desktop: 7

Red Hat Enterprise Linux Workstation: 7

Red Hat Enterprise Linux Server: 7

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CPE2.3

• cpe:2.3:o:red_hat:kernel:3.10.0-327.100.1.el7:*:*:*:*:red_hat_enterprise_linux:*:*
• Full software list in CPE2.3 format available after registration.

External links

http://access.redhat.com/errata/RHSA-2021:3438

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.