CVE-2019-16161
Description
A NULL pointer dereference vulnerability was found in Onigmo in the way it handled certain types of "subexp" regular expressions. A remote attacker could exploit this flaw by providing a malformed regular expression that when processed by an application linked to Onigmo, would crash the application, causing a denial of service.
Statement
This flaw does not affect the versions of oniguruma (embedded in php:7.2/php) as shipped with Red Hat Enterprise Linux 8 as they do not include the vulnerable code, which was introduced in a newer version of the package. The same is true for the versions of oniguruma as shipped with Red Hat Enterprise Linux 6, the versions of oniguruma (embedded in php and php53) as shipped with Red Hat Enterprise Linux 5, 6, and 7, and the versions of oniguruma (embedded in rh-php72-php) as shipped with Red Hat Software Collections 3.
This flaw does not affect the versions of oniguruma as shipped with Red Hat Enterprise Linux 8 as they already include the patch. The same is true for the versions of oniguruma (embedded in php:7.3/php) as shipped with Red Hat Enterprise Linux 8 and the versions of oniguruma (embedded in rh-php73-php) as shipped with Red Hat Software Collections 3.
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 | 7.5 | 7.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | 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:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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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