CVE Vulnerabilities


Use After Free

Published: Jul 10, 2019 | Modified: Nov 07, 2023
CVSS 3.x
CVSS 2.x
7.5 HIGH

A use-after-free in onig_new_deluxe() in regext.c in Oniguruma 6.9.2 allows attackers to potentially cause information disclosure, denial of service, or possibly code execution by providing a crafted regular expression. The attacker provides a pair of a regex pattern and a string, with a multi-byte encoding that gets handled by onig_new_deluxe(). Oniguruma issues often affect Ruby, as well as common optional libraries for PHP and Rust.


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
Oniguruma Oniguruma_project 6.9.2 (including) 6.9.2 (including)
Red Hat Enterprise Linux 8 RedHat php:7.3-8020020200715124551.ceb1cf90 *
Red Hat Enterprise Linux 8 RedHat oniguruma-0:6.8.2-2.1.el8_9 *
Red Hat Enterprise Linux 8.6 Extended Update Support RedHat oniguruma-0:6.8.2-2.1.el8_6 *
Red Hat Enterprise Linux 8.8 Extended Update Support RedHat oniguruma-0:6.8.2-2.1.el8_8 *
Groonga Ubuntu bionic *
Groonga Ubuntu cosmic *
Groonga Ubuntu devel *
Groonga Ubuntu disco *
Groonga Ubuntu eoan *
Groonga Ubuntu esm-apps/bionic *
Groonga Ubuntu esm-apps/focal *
Groonga Ubuntu esm-apps/jammy *
Groonga Ubuntu esm-apps/noble *
Groonga Ubuntu esm-apps/xenial *
Groonga Ubuntu focal *
Groonga Ubuntu groovy *
Groonga Ubuntu hirsute *
Groonga Ubuntu impish *
Groonga Ubuntu jammy *
Groonga Ubuntu kinetic *
Groonga Ubuntu lunar *
Groonga Ubuntu mantic *
Groonga Ubuntu noble *
Groonga Ubuntu trusty *
Groonga Ubuntu xenial *
Libevhtp Ubuntu esm-apps/xenial *
Libevhtp Ubuntu trusty *
Libevhtp Ubuntu xenial *
Libonig Ubuntu bionic *
Libonig Ubuntu cosmic *
Libonig Ubuntu devel *
Libonig Ubuntu disco *
Libonig Ubuntu eoan *
Libonig Ubuntu esm-apps/bionic *
Libonig Ubuntu esm-apps/focal *
Libonig Ubuntu esm-apps/xenial *
Libonig Ubuntu focal *
Libonig Ubuntu groovy *
Libonig Ubuntu hirsute *
Libonig Ubuntu impish *
Libonig Ubuntu jammy *
Libonig Ubuntu kinetic *
Libonig Ubuntu lunar *
Libonig Ubuntu mantic *
Libonig Ubuntu noble *
Libonig Ubuntu trusty *
Libonig Ubuntu trusty/esm *
Libonig Ubuntu xenial *
Mudlet Ubuntu bionic *
Mudlet Ubuntu cosmic *
Mudlet Ubuntu disco *
Mudlet Ubuntu eoan *
Mudlet Ubuntu esm-apps/bionic *
Mudlet Ubuntu esm-apps/focal *
Mudlet Ubuntu esm-apps/xenial *
Mudlet Ubuntu focal *
Mudlet Ubuntu trusty *
Mudlet Ubuntu xenial *
Php5 Ubuntu precise/esm *
Php5 Ubuntu trusty/esm *

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