CVE-2019-11837 : Vulnerability Insights and Analysis

Version 0.3.1 of njs, which is utilized in NGINX, experiences a segmentation fault when encountering negative arguments in the String.prototype.toBytes function. This issue is connected to nxt_utf8_next in nxt/nxt_utf8.h and njs_string_offset in njs/njs_string.c.

Understanding CVE-2019-11837

This CVE involves a vulnerability in njs through version 0.3.1, which is used in NGINX, leading to a segmentation fault under specific conditions.

What is CVE-2019-11837?

CVE-2019-11837 is a vulnerability in the njs module, affecting NGINX, that triggers a segmentation fault when negative arguments are encountered in the String.prototype.toBytes function.

The Impact of CVE-2019-11837

The vulnerability can be exploited by an attacker to cause a denial of service (DoS) condition by crashing the affected NGINX server.

Technical Details of CVE-2019-11837

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The issue arises in njs through version 0.3.1, impacting NGINX, due to a segmentation fault in the String.prototype.toBytes function when negative arguments are processed.

Affected Systems and Versions

Product: n/a
Vendor: n/a
Versions: n/a

Exploitation Mechanism

The vulnerability is exploited by providing negative arguments to the String.prototype.toBytes function, triggering a segmentation fault in the affected software components.

Mitigation and Prevention

To address CVE-2019-11837 and enhance system security, follow these mitigation strategies:

Immediate Steps to Take

Apply vendor patches or updates promptly.
Monitor NGINX server logs for any unusual activity.

Long-Term Security Practices

Regularly update NGINX and its associated modules.
Implement network security measures to detect and prevent DoS attacks.

Patching and Updates

Ensure that NGINX and the njs module are kept up to date with the latest security patches to mitigate the risk of exploitation.