CVE-2026-66785: Input Validation Flaw (CVSS 9.9)

Description

A flaw was found in Submariner. This vulnerability allows a malicious cluster (spoke) to redirect network traffic from other connected clusters (peer clusters) by publishing a specially crafted network endpoint. The system fails to properly validate the network subnets provided by the malicious cluster, enabling it to declare arbitrary network ranges. Consequently, all network traffic intended for these arbitrary ranges from peer clusters will be rerouted through the attacker's tunnel, potentially leading to unauthorized information disclosure or network disruption.

Is your site exposed to CVE-2026-66785?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

9.9

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0010

Probability of exploitation

0.01%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-20 Improper Input Validation

References

Other References

https://access.redhat.com/security/cve/CVE-2026-66785 https://bugzilla.redhat.com/show_bug.cgi?id=2507530

Frequently Asked Questions

What is CVE-2026-66785? +

A flaw was found in Submariner. This vulnerability allows a malicious cluster (spoke) to redirect network traffic from other connected clusters (peer clusters) by publishing a specially crafted network endpoint. The system fails to properly validate the network subnets provided by the malicious cluster, enabling it to declare arbitrary network ranges. Consequently, all network traffic intended for these arbitrary ranges from peer clusters will be rerouted through the attacker's tunnel, potentially leading to unauthorized information disclosure or network disruption. It has a CVSS v3.1 base score of 9.9 (CRITICAL).

How severe is CVE-2026-66785? +

CVE-2026-66785 has a CVSS v3.1 score of 9.9 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0010, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-66785? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-84357

Improper input validation in Omnibox in Google Chrome prior to 152.0.7977.75 allowed a remote attacker leveraging social engineering to bypass …

CVE-2025-13826

Zervit's portable HTTP/web server is vulnerable to remote DoS attacks when a configuration reset request is made. The vulnerability is …

CVE-2026-62658

A security flaw was discovered in certain NETGEAR Nighthawk RAX series routers that could allow someone already logged in to …

CVE-2024-54011

Penetration Testing engineers at Amazon have discovered a flaw where the camera system fails to properly handle data supplied in …

CVE-2026-56349

n8n before version 2.10.0 contains an input validation vulnerability in the Guardrail node that allows attackers to bypass default guardrail …

CVE-2026-6409

A Denial of Service (DoS) vulnerability exists in the Protobuf PHP library during the parsing of untrusted input. Maliciously structured …

CVE-2026-66785