Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-42945

Severity CVSS v4.0:
CRITICAL
Type:
CWE-122 Heap-based Buffer Overflow
Publication date:
13/05/2026
Last modified:
27/06/2026

Description

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when the rewrite directive is followed by a rewrite, if, or set directive and an unnamed Perl-Compatible Regular Expression (PCRE) capture (for example, $1, $2) with a replacement string that includes a question mark (?). An unauthenticated attacker along with conditions beyond its 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.

Impact

Vector 4.0
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 9.20 CRITICAL
Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Attack Requirements (AT): None
Privileges Required (PR): None
User Interaction (UI): None
Confidentiality (VC): High
Integrity (VI): High
Availability (VA): High
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None

Base Score 4.0
9.20
Severity 4.0
CRITICAL
Vector 3.x
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 8.10 HIGH
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x
8.10
Severity 3.x
HIGH

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:f5:dos:*:*:*:*:*:nginx:*:* 4.3.0 (including) 4.7.0 (including)
cpe:2.3:a:f5:dos:4.8.0:*:*:*:*:nginx:*:*
cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:* 1.3.0 (including) 1.6.2 (including)
cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:* 2.0.0 (including) 2.5.1 (including)
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:* 3.5.0 (including) 3.7.2 (including)
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:* 4.0.0 (including) 4.0.1 (including)
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:* 5.0.0 (including) 5.4.1 (including)
cpe:2.3:a:f5:nginx_instance_manager:*:*:*:*:*:*:*:* 2.16.0 (including) 2.21.1 (including)
cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:* 0.6.27 (including) 1.30.0 (including)
cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:* r32 (including) r36 (including)
cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:* 4.9.0 (including) 4.16.0 (including)
cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:* 5.1.0 (including) 5.8.0 (including)
cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:* 5.9.0 (including) 5.12.1 (including)

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools