CVE-2023-27491: exploitation status and patch state

CVE-2023-27491 · CVSS 5.4 MEDIUM · EPSS 1%

Envoy is an open source edge and service proxy designed for cloud-native applications. Compliant HTTP/1 service should reject malformed request lines. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, There is a possibility that non compliant HTTP/1 service may allow malformed requests, potentially leading to a bypass of security policies. This issue is fixed in versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9.

Is CVE-2023-27491 exploited?

• Not in the CISA KEV catalog.
• EPSS puts exploitation in the next 30 days at 1%.
• Public exploit code: none found in monitored sources.

Which products and versions are affected?

No affected package list recorded here yet.

Is there a patch?

No patch identifier recorded here yet.

What PlainSec published about CVE-2023-27491

• Node Kernel Bugs on GKE COS Nodes Enable Host Escalation (2026-04-15)
• Google Cloud Issues Multiple Linux Kernel Privilege Escalation Fixes for GKE Nodes (2026-04-07)
• Multiple Linux Kernel Flaws Elevate Privileges on GCP Container Nodes (2026-04-03)
• Multiple High-Severity Cloud Vulnerabilities Impact Container Nodes (2026-04-01)

Primary sources

• NVD record

What this record does not say

• No affected package data.
• No patch identifier.

KEV and EPSS are re-checked daily. Record last updated 2026-08-15.