CVE-2026-9256 (GCVE-0-2026-9256)
Vulnerability from cvelistv5
Published
2026-05-22 14:11
Modified
2026-08-25 12:05
Severity ?
8.1 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
9.2 (Critical) - CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CWE
  • CWE-122 - Heap-based Buffer Overflow
Summary
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
Impacted products
Vendor Product Version
F5 NGINX Plus Version: 37.0   < 37.0.1.1
Version: R36   < R36 P5
Version: R32   < R32 P7
 Create a notification for this product.
   F5 NGINX Open Source Version: 1.31.0   < 1.31.1
Version: 1.30.0   < 1.30.2
Version: 0.1.17   <
Create a notification for this product.
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  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.