NetSight
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high8.1

CVE-2026-9256

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module.

Impact

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.

Affected products

VendorProductAffected versions
F5Nginx Open Source
from 0.1.17 through 0.9.7
from 1.0.0 before 1.30.2
Version 1.31.0
F5Nginx Plus
from r33 before r36
Versions 37.0.0.1, r32, r36
F5Dos
from 4.3.0 through 4.7.0
Version 4.9.0
F5Nginx Gateway Fabric
from 1.3.0 through 1.6.2
from 2.0.0 before 2.6.2
F5Nginx Ingress Controller
from 3.5.0 through 3.7.2
from 4.0.0 through 4.0.1
from 5.0.0 before 5.4.3
F5Nginx Instance Manager
from 2.17.0 before 2.22.1
F5Waf
from 4.10.0 through 4.16.0
from 5.2.0 through 5.8.0
from 5.9.0 through 5.13.0
RedhatDiscovery
All versions
RedhatHardened Images
All versions
RedhatUpdate Infrastructure
from 5.0 before 5.2
DebianDebian Linux
Version 11.0
RedhatEnterprise Linux
Versions 8.0, 9.0, 10.0

Weakness classification

CWE-122

References