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.
References
| Link | Resource |
|---|---|
| https://my.f5.com/manage/s/article/K000161377 | Mitigation Vendor Advisory |
| http://www.openwall.com/lists/oss-security/2026/05/22/14 | Mailing List Third Party Advisory |
Configurations
Configuration 1 (hide)
|
History
16 Jun 2026, 19:59
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:* cpe:2.3:a:f5:nginx_open_source:1.31.0:*:*:*:*:*:*:* cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:* |
|
| First Time |
F5 nginx Open Source
F5 F5 nginx Plus |
|
| References | () https://my.f5.com/manage/s/article/K000161377 - Mitigation, Vendor Advisory | |
| References | () http://www.openwall.com/lists/oss-security/2026/05/22/14 - Mailing List, Third Party Advisory |
23 May 2026, 01:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-05-22 15:16
Updated : 2026-06-16 19:59
NVD link : CVE-2026-9256
Mitre link : CVE-2026-9256
CVE.ORG link : CVE-2026-9256
JSON object : View
Products Affected
f5
- nginx_plus
- nginx_open_source
CWE
CWE-122
Heap-based Buffer Overflow