CVE-2026-90651: socket socket firewall Improper Certificate Validation

Vulnerability summary

CVE-2026-90651 is a high (CVSS 8.1) Improper Certificate Validation vulnerability in socket socket firewall. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 9.9% of scored vulnerabilities.

Timeline

1. 12-09-2026
   PublishedVulnerability first disclosed.
2. 14-09-2026
   Last modifiedVulnerability information updated.

Description

Socket Firewall (socketdev/socket-registry-firewall) in registry mode before 2.0.0 does not verify upstream TLS certificates by default. When the api_ssl_verify and upstream_ssl_verify configuration keys are omitted from socket.yml, the generated configuration sets SOCKET_API_SSL_VERIFY='false' and UPSTREAM_SSL_VERIFY='false', and the OpenResty/Lua HTTP client used for outbound requests accepts any certificate, including self-signed and otherwise untrusted certificates, without validating the chain. An attacker positioned to intercept traffic between Socket Firewall and the Socket API or an upstream package registry can present a crafted certificate and modify responses in transit, including substituting malicious package content or altering the allow/block decisions the firewall enforces. Setting api_ssl_verify: true and upstream_ssl_verify: true enables verification; however, in versions before 1.1.334, the generated nginx configuration did not emit lua_ssl_trusted_certificate, and thus verification could not be used successfully without manually patching the generated configuration. Version 2.0.0 changes the default for both settings to true.

• CWE-295Improper Certificate ValidationThe product does not validate, or incorrectly validates, a certificate.