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vulnerability context

CVE-2026-9256

CVSS 8.1 HIGHEPSS 23%CWE-122

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...

Published 2026-05-22 · last modified 2026-05-23

details

CISA KEV status
Not in catalog
CVSS v3
8.1 / HIGH
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
23% percentile (score 0.0008)
CWE
CWE-122

source mentions 5

source consensus

  • Bluesky
  • MSRC Update Guide
  • oss-security
  • r/netsec
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