NGINX Software Can Crash or Be Hacked with Malicious Requests

Summary

NGINX software has a weakness that can be exploited by sending specially crafted HTTP requests. This could cause the software to crash or, in some cases, allow an attacker to take control of the system. If you're using NGINX, update to the latest version to ensure you have the fix.

What to do

Update nginx to version 1.28.3-r1.

Affected software

Ecosystem	Vendor	Product	Affected versions
Alpine:v3.22	–	nginx	< 1.28.3-r1 Fix: upgrade to 1.28.3-r1
Alpine:v3.23	–	nginx	< 1.28.3-r1 Fix: upgrade to 1.28.3-r1

Original title

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when the rewrite directive is followed by a rewrite, if, or set directive and ...

Original description

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when the rewrite directive is followed by a rewrite, if, or set directive and an unnamed Perl-Compatible Regular Expression (PCRE) capture (for example, $1, $2) with a replacement string that includes a question mark (?). An unauthenticated attacker along with conditions beyond its control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

osv CVSS4.0 9.4

https://security.alpinelinux.org/vuln/CVE-2026-42945 Vendor Advisory