Summary
Envoy Gateway: OCI layer extraction allocates make([]byte, h.Size) from untrusted tar header
Vulnerability report without repro case. Repro case may be added later after harness is complete.
Preconditions (4):
- Tenant can create EnvoyExtensionPolicy (baseline)
- Controller has egress to attacker-controlled OCI registry
- No registry allowlist (none exists in code)
- Layer presents Docker/OCI media type
Description
At imagefetcher.go:287, make([]byte, h.Size) uses the attacker-controlled tar-header size; the LimitReader at :278 bounds bytes read from the stream but not the header-declared size returned by tr.Next() (a 512-byte header can claim a multi-TB entry via PAX/GNU encoding). Reached from untrusted tenant input via EnvoyExtensionPolicy spec.wasm[].code.image.url (envoyextensionpolicy.go:1157 → cache.go:262/299 → imagefetcher.go:218 → :287), and the allocation happens for every tar entry regardless of filename. The resulting Go runtime OOM throw is unrecoverable and, because the CRD persists, crash-loops the shared controller, single-request, non-volumetric, cluster-wide DoS.
Impact
CVE-2026-53717 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.8.1, 1.7.4); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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github.com/envoyproxy/gateway to 1.8.1 or later; github.com/envoyproxy/gateway to 1.7.4 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-53717? CVE-2026-53717 is a medium-severity security vulnerability in github.com/envoyproxy/gateway (go), affecting versions >= 1.8.0-rc.0, < 1.8.1. It is fixed in 1.8.1, 1.7.4.
- How severe is CVE-2026-53717? CVE-2026-53717 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/envoyproxy/gateway are affected by CVE-2026-53717? github.com/envoyproxy/gateway (go) versions >= 1.8.0-rc.0, < 1.8.1 is affected.
- Is there a fix for CVE-2026-53717? Yes. CVE-2026-53717 is fixed in 1.8.1, 1.7.4. Upgrade to this version or later.
- Is CVE-2026-53717 exploitable, and should I be worried? Whether CVE-2026-53717 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-53717 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-53717?
- Upgrade
github.com/envoyproxy/gatewayto 1.8.1 or later - Upgrade
github.com/envoyproxy/gatewayto 1.7.4 or later
- Upgrade