CVE-2026-90651 Socket CVE debrief

Who should care

Defenders responsible for Socket Firewall instances, especially those using versions before 2.0.0, should assess exposure and ensure proper TLS verification is enabled to prevent potential traffic interception and modification.

Why it matters

CVE-2026-90651 is significant because it allows attackers to intercept and modify traffic due to the lack of default TLS verification in Socket Firewall versions before 2.0.0. Defenders should assess exposure, verify configuration, and consider updating to mitigate potential risks.

• An attacker can intercept and modify traffic between Socket Firewall and the Socket API or upstream package registries.
• Malicious package content can be substituted or allow/block decisions can be altered.
• Defenders need to verify exposure and assess configuration for Socket Firewall instances.
• Remediation involves updating to version 2.0.0 or later and ensuring TLS verification is enabled.

Technical summary

Socket Firewall in registry mode before version 2.0.0 does not verify upstream TLS certificates by default. This allows an attacker to intercept traffic between Socket Firewall and the Socket API or an upstream package registry, potentially leading to malicious package content substitution or alteration of allow/block decisions. The vulnerability arises from the default configuration of SOCKET_API_SSL_VERIFY='false' and UPSTREAM_SSL_VERIFY='false' in socket.yml. 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. To 2.

Defensive priority

Defenders should prioritize verifying exposure and assessing configuration for Socket Firewall instances, especially those using versions before 2.0.0, and ensure proper TLS verification is enabled.

Recommended defensive actions

• Verify Socket Firewall configuration to ensure TLS verification is enabled
• Assess exposure for Socket Firewall instances, especially those using versions before 2.0.0
• Update to version 2.0.0 or later if possible
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability in Socket Firewall, which does not verify upstream TLS certificates by default in versions before 2.0.0. This could allow an attacker to intercept traffic and modify responses.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.