CVE-2020-29660

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Last Modified: UTC

ModerateModerate ImpactWhat does this mean?

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Description

A locking inconsistency issue was discovered in the tty subsystem of the Linux kernel. A local user could use this flaw to read numerical value from memory after free.

A locking inconsistency issue was discovered in the tty subsystem of the Linux kernel. A local user could use this flaw to read numerical value from memory after free.

Statement

This flaw is rated as having Low impact (Red Hat Enterprise Linux 7) because of the need to have CAP_SYS_TTY_CONFIG privileges. This flaw is rated as having Moderate (Red Hat Enterprise Linux 8) impact because of the need to have CAP_SYS_TTY_CONFIG privileges. Red Hat Enterprise Linux 8 enabled unprivileged user/network namespaces by default which can be used to exercise this vulnerability.

This flaw is rated as having Low impact (Red Hat Enterprise Linux 7) because of the need to have CAP_SYS_TTY_CONFIG privileges.

This flaw is rated as having Moderate (Red Hat Enterprise Linux 8) impact because of the need to have CAP_SYS_TTY_CONFIG privileges. Red Hat Enterprise Linux 8 enabled unprivileged user/network namespaces by default which can be used to exercise this vulnerability.

Mitigation

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Additional information

  • Bugzilla 1906522: kernel: locking inconsistency in drivers/tty/tty_io.c and drivers/tty/tty_jobctrl.c can lead to a read-after-free
  • CWE-667->CWE-416: Improper Locking leads to Use After Free
  • FAQ: Frequently asked questions about CVE-2020-29660

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

CVSS v3 Score Breakdown
Red HatNVD

CVSS v3 Base Score

4.4

4.4

Attack Vector

Local

Local

Attack Complexity

Low

Low

Privileges Required

High

High

User Interaction

None

None

Scope

Unchanged

Unchanged

Confidentiality Impact

High

High

Integrity Impact

None

None

Availability Impact

None

None

CVSS v3 Vector

Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

NVD: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?

What can I do if my product is listed as "Will not fix"?

What can I do if my product is listed as "Fix deferred"?

What is a mitigation?

I have a Red Hat product but it is not in the above list, is it affected?

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

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