CVE-2026-40701 PUBLISHED

NGINX ngx_http_ssl_module vulnerability

Assigner: f5
Reserved: 30.04.2026 Published: 13.05.2026 Updated: 13.05.2026

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.

Metrics

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
CVSS Score: 6.3

Product Status

Vendor F5
Product NGINX Plus
Versions Default: unknown
  • unaffected from R37 to * (excl.)
  • affected from R36 to R36 P4 (excl.)
  • affected from R32 to R32 P6 (excl.)
Vendor F5
Product NGINX Open Source
Versions Default: unaffected
  • unaffected from 1.31.0 to * (excl.)
  • affected from 1.19.0 to 1.30.1 (excl.)

Credits

  • F5 acknowledges Zhenpeng (Leo) Lin of depthfirst for bringing this issue to our attention and following the highest standards of coordinated disclosure. finder

References

Problem Types

  • CWE-416 Use After Free CWE