CVE Vulnerabilities

CVE-2020-11558

Use After Free

Published: Apr 05, 2020 | Modified: Apr 06, 2020
CVSS 3.x
9.8
CRITICAL
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
7.5 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu
MEDIUM

An issue was discovered in libgpac.a in GPAC 0.8.0, as demonstrated by MP4Box. audio_sample_entry_Read in isomedia/box_code_base.c does not properly decide when to make gf_isom_box_del calls. This leads to various use-after-free outcomes involving mdia_Read, gf_isom_delete_movie, and gf_isom_parse_movie_boxes.

Weakness

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software

Name Vendor Start Version End Version
Gpac Gpac 0.8.0 (including) 0.8.0 (including)
Ccextractor Ubuntu eoan *
Ccextractor Ubuntu groovy *
Ccextractor Ubuntu hirsute *
Ccextractor Ubuntu impish *
Ccextractor Ubuntu trusty *
Gpac Ubuntu bionic *
Gpac Ubuntu eoan *
Gpac Ubuntu groovy *
Gpac Ubuntu trusty *
Gpac Ubuntu xenial *

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations

References