CVE-2026-9256
概要

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.

公表日 2026年5月23日0:16
登録日 2026年5月27日4:05
最終更新日 2026年5月23日10:16
CVSS3.1 : HIGH
スコア 8.1
ベクター CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
攻撃元区分(AV) ネットワーク
攻撃条件の複雑さ(AC)
攻撃に必要な特権レベル(PR) 不要
利用者の関与(UI) 不要
影響の想定範囲(S) 変更なし
機密性への影響(C)
完全性への影響(I)
可用性への影響(A)
関連情報、対策とツール
共通脆弱性一覧