CVE-2026-9256

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.

Affected Software

VendorProductVersion RangeStatus
F5NGINX Plus37.0 < 37.0.1.1affected
F5NGINX PlusR36 < R36 P5affected
F5NGINX PlusR32 < R32 P7affected
F5NGINX Open Source1.31.0 < 1.31.1affected
F5NGINX Open Source1.30.0 < 1.30.2affected
F5NGINX Open Source0.1.17 <= 0.9.7affected

Weaknesses

  • CWE-122: CWE-122 Heap-based Buffer Overflow

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: total

CVE Program Container

Additional References

nginx: ngx_http_rewrite_module: code execution and denial of service

Additional References

References