CVE-2026-53717: Envoy Gateway: OCI layer extraction allocates make([]byte, h.Size) from untrusted tar header

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-14 · updated 2026-09-30
Weakness: CWE-789

Description

Envoy Gateway is an open source project for managing Envoy Proxy as a standalone or Kubernetes-based application gateway. Prior to 1.7.4 and 1.8.1, internal/wasm/imagefetcher.go follows tenant-controlled EnvoyExtensionPolicy spec.wasm[].code.image.url values to Docker or OCI Wasm layers, and extractWasmPluginBinary uses the untrusted tar-header h.Size value to allocate memory before validating the entry name or declared size. A small PAX or GNU tar header can therefore claim a multi-terabyte entry even though the surrounding LimitReader restricts only the bytes read from the stream, and no registry allowlist prevents a permitted tenant from selecting an attacker-controlled registry that the controller can reach. The allocation is attempted for every tar entry and can cause an unrecoverable Go runtime out-of-memory failure; because the custom resource persists, reconciliation repeatedly crash-loops the shared controller and causes a single-request, non-volumetric, cluster-wide control-plane denial of service. This issue is fixed in versions 1.7.4 and 1.8.1.

Affected products

envoyproxy gateway: before 1.7.4; from 1.8.0-rc.0, < 1.8.1

References

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