CVE-2026-26308
7.5 · HIGHOverview
CVE-2026-26308 is a high-severity vulnerability affecting envoyproxy envoy. It was published on March 10, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, the Envoy RBAC (Role-Based Access Control) filter contains a logic vulnerability in how it validates HTTP headers when multiple values are present for the same header name. Instead of validating each header value individually, Envoy concatenates all values into a single comma-separated string. This behavior allows attackers to bypass RBAC policies—specifically "Deny" rules—by sending duplicate headers, effectively obscuring the malicious value from exact-match mechanisms. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.
Remediation
Check the references section for vendor advisories and patches from envoyproxy. Update envoy to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| envoyproxy | envoy | >= 0, < 1.34.13 | Affected |
Frequently Asked Questions
What is CVE-2026-26308?
CVE-2026-26308 is a high-severity vulnerability affecting envoyproxy envoy. It was published on March 10, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-26308?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-26308?
Check the references section for vendor advisories and patches from envoyproxy. Update envoy to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-26308?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-26308 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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