CVE-2026-9256
Public on 2026-05-22
Modified on 2026-05-22
Description
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. An unauthenticated attacker along with conditions beyond their 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.
Severity
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CVSS v3 Base Score
See breakdown
Affected Packages
| Platform | Package | Release Date | Advisory | Status |
|---|---|---|---|---|
| Amazon Linux 2 - Nginx1 Extra | nginx | Pending Fix | ||
| Amazon Linux 2023 | nginx | Pending Fix |
CVSS Scores
| Score Type | Score | Vector | |
|---|---|---|---|
| Amazon Linux | CVSSv3 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |