CVE Vulnerabilities

CVE-2024-0408

Improper Neutralization of Null Byte or NUL Character

Published: Jan 18, 2024 | Modified: Nov 21, 2024
CVSS 3.x
5.5
MEDIUM
Source:
NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
5.5 IMPORTANT
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Ubuntu
MEDIUM

A flaw was found in the X.Org server. The GLX PBuffer code does not call the XACE hook when creating the buffer, leaving it unlabeled. When the client issues another request to access that resource (as with a GetGeometry) or when it creates another resource that needs to access that buffer, such as a GC, the XSELINUX code will try to use an object that was never labeled and crash because the SID is NULL.

Weakness

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes NUL characters or null bytes when they are sent to a downstream component.

Affected Software

Name Vendor Start Version End Version
Tigervnc Tigervnc * 1.13.1 (excluding)
Xorg-server X.org * 21.1.11 (excluding)
Xwayland X.org * 23.2.4 (excluding)
Red Hat Enterprise Linux 7 RedHat xorg-x11-server-0:1.20.4-27.el7_9 *
Red Hat Enterprise Linux 8 RedHat xorg-x11-server-0:1.20.11-22.el8 *
Red Hat Enterprise Linux 8 RedHat xorg-x11-server-Xwayland-0:21.1.3-15.el8 *
Red Hat Enterprise Linux 9 RedHat xorg-x11-server-0:1.20.11-24.el9 *
Red Hat Enterprise Linux 9 RedHat xorg-x11-server-Xwayland-0:22.1.9-5.el9 *
Xorg Ubuntu bionic *
Xorg Ubuntu trusty *
Xorg Ubuntu xenial *
Xorg-server Ubuntu bionic *
Xorg-server Ubuntu devel *
Xorg-server Ubuntu esm-infra/bionic *
Xorg-server Ubuntu esm-infra/xenial *
Xorg-server Ubuntu focal *
Xorg-server Ubuntu jammy *
Xorg-server Ubuntu lunar *
Xorg-server Ubuntu mantic *
Xorg-server Ubuntu noble *
Xorg-server Ubuntu oracular *
Xorg-server Ubuntu trusty *
Xorg-server Ubuntu trusty/esm *
Xorg-server Ubuntu upstream *
Xorg-server Ubuntu xenial *
Xorg-server-hwe-16.04 Ubuntu xenial *
Xorg-server-hwe-18.04 Ubuntu bionic *
Xorg-server-lts-utopic Ubuntu trusty *
Xorg-server-lts-vivid Ubuntu trusty *
Xorg-server-lts-wily Ubuntu trusty *
Xorg-server-lts-xenial Ubuntu trusty *
Xwayland Ubuntu devel *
Xwayland Ubuntu jammy *
Xwayland Ubuntu lunar *
Xwayland Ubuntu mantic *
Xwayland Ubuntu noble *
Xwayland Ubuntu oracular *

Potential Mitigations

  • Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

References