CVE-2026-40701

CVE Enrichment

CVSS: 6.3 MEDIUM
EPSS: 0.69%
EPSS Percentile: 52.79%
CISA KEV: Not listed

Description

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssl_module module when the ssl_verify_client directive is set to "on" or "optional," and the ssl_ocsp directive is set to "on" or the leaf parameters are configured with a resolver. With this configuration, an unauthenticated attacker can send requests along with conditions beyond its control that may cause a heap-use-after-free error in the NGINX worker process. This vulnerability may result in limited modification of data or the NGINX worker process restarting. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Technical Details

CVSS Version: 4.0
CNA / NVD Source: [email protected]
Published: 13-May-2026 23:16
Last Modified: 27-Oct-2026 00:10
EPSS Date: 2026-11-02
CWE: CWE-416

CVSS Vector


            CVSS:4.0                            AV:N /
                            AC:L /
                            AT:P /
                            PR:N /
                            UI:N /
                            VC:L /
                            VI:N /
                            VA:L /
                            SC:N /
                            SI:N /
                            SA:N /
                            E:X /
                            CR:X /
                            IR:X /
                            AR:X /
                            MAV:X /
                            MAC:X /
                            MAT:X /
                            MPR:X /
                            MUI:X /
                            MVC:X /
                            MVI:X /
                            MVA:X /
                            MSC:X /
                            MSI:X /
                            MSA:X /
                            S:X /
                            AU:X /
                            R:X /
                            V:X /
                            RE:X /
                            U:X

CNA Products / Version Status

F5 · NGINX Open Source Source: CNA · [email protected]
Default status: unaffected

1.31.0 ≤ version < * — unaffected (semver)
1.19.0 ≤ version < 1.30.1 — affected (semver)

Modules: ngx_http_ssl_module
F5 · NGINX Plus Source: CNA · [email protected]
Default status: unknown

R37 ≤ version < * — unaffected (custom)
R36 ≤ version < R36 P4 — affected (custom)
R32 ≤ version < R32 P6 — affected (custom)

Modules: ngx_http_ssl_module

Affected Products / Versions

f5 / dos Source: NVD CPE · affected
Version / affected range: * · from (inclusive) 4.3.0 · through (inclusive) 4.7.0
cpe:2.3:a:f5:dos:*:*:*:*:*:nginx:*:*
f5 / dos Source: NVD CPE · affected
Version / affected range: 4.8.0
cpe:2.3:a:f5:dos:4.8.0:*:*:*:*:nginx:*:*
f5 / nginx_gateway_fabric Source: NVD CPE · affected
Version / affected range: * · from (inclusive) 1.3.0 · through (inclusive) 1.6.2
cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:*
f5 / nginx_gateway_fabric Source: NVD CPE · affected
Version / affected range: * · from (inclusive) 2.0.0 · through (inclusive) 2.6.0
cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:*
f5 / nginx_ingress_controller Source: NVD CPE · affected
Version / affected range: * · from (inclusive) 3.5.0 · through (inclusive) 3.7.2
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*
f5 / nginx_ingress_controller Source: NVD CPE · affected
Version / affected range: * · from (inclusive) 4.0.0 · through (inclusive) 4.0.1
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*
f5 / nginx_ingress_controller Source: NVD CPE · affected
Version / affected range: * · from (inclusive) 5.0.0 · through (inclusive) 5.4.2
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*
f5 / nginx_instance_manager Source: NVD CPE · affected
Version / affected range: * · from (inclusive) 2.16.0 · through (inclusive) 2.22.0
cpe:2.3:a:f5:nginx_instance_manager:*:*:*:*:*:*:*:*
f5 / nginx_open_source Source: NVD CPE · affected
Version / affected range: * · from (inclusive) 1.19.0 · through (inclusive) 1.30.0
cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*
f5 / nginx_plus Source: NVD CPE · affected
Version / affected range: * · from (inclusive) r32 · through (inclusive) r36
cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:*
f5 / waf Source: NVD CPE · affected
Version / affected range: * · from (inclusive) 4.9.0 · through (inclusive) 4.16.0
cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:*
f5 / waf Source: NVD CPE · affected
Version / affected range: * · from (inclusive) 5.1.0 · through (inclusive) 5.8.0
cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:*
f5 / waf Source: NVD CPE · affected
Version / affected range: * · from (inclusive) 5.9.0 · through (inclusive) 5.12.1
cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:*

References

[email protected]

Last enrichment sync: 03-Nov-2026 18:46
Sources: NVD · FIRST EPSS · CISA KEV
Latest successful provider update; providers refresh independently.

Reported Context (2)

CVE-2026-40701 — use-after-free in asynchronous OCSP DNS resolution handling (medium severity) 18-Year-Old NGINX Flaw Can Cause DoS, With RCE Demonstrated Under Specific Conditions
CVE-2026-40701 (CVSS v4 score: 6.3) – A use-after-free vulnerability in the ngx_http_ssl_module module that could allow a remote, unauthenticated attacker to have limited control of modification of data or restart the 18-Year-Old NGINX Rewrite Flaw Could Enable Unauthenticated RCE

CVE (3)

People (1)

MITRE ATT&CK (2)

Vendors (1)

Products (10)

Industries (3)

Note: Related entities, including threat actors, malware, CVEs, MITRE ATT&CK techniques, vendors, products, tools, countries, and industries, are shown when they appear in the same reporting. Their presence does not necessarily mean they were targeted, compromised, vulnerable, responsible for the activity, or directly involved in the incident.