CVE-2022-2085
Description
A NULL pointer dereference vulnerability was found in Ghostscript, which occurs when it tries to render a large number of bits in memory. When allocating a buffer device, it relies on an init_device_procs defined for the device that uses it as a prototype that depends upon the number of bits per pixel. For bpp > 64, mem_x_device is used and does not have an init_device_procs defined. This flaw allows an attacker to parse a large number of bits (more than 64 bits per pixel), which triggers a NULL pointer dereference flaw, causing an application to crash.
Statement
This is a fairly hard case, as very few devices use more than 64 bits per pixel. The DeviceN device is one of the few that does, and then the problem only kicks in if the MaxBitmap figure is high enough (or conversely the resolution is low enough).
Common Vulnerability Scoring System (CVSS) Score Details
Info alert: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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | 5.5 | N/A |
| Attack Vector | Network | Local | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | Required | Required | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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