Medium [CVE-2026-40701] 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
This medium-severity F5 advisory covers CVE-2026-40701 affecting NGINX Plus, NGINX.
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Summary
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.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 2 months ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 2 months ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 2 months ago·verify at source
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