CVE-2026-53717
MEDIUMCVE-2026-53717 is a medium-severity (CVSS 6.5) vulnerability in github.com/envoyproxy/gateway. O3 Security confirms whether CVE-2026-53717 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Envoy Gateway: OCI layer extraction allocates make([]byte, h.Size) from untrusted tar header
Real-World Exposure
github.com/envoyproxy/gateway🐹github.com/envoyproxy/gatewayReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/envoyproxy/gateway | ≥ 1.8.0-rc.0&&< 1.8.1 | 1.8.1 |
| 🐹Go | github.com/envoyproxy/gateway | all versions | 1.7.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/envoyproxy/gateway. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/envoyproxy/gateway to 1.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-53717 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-53717 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-53717. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-53717 in your dependencies?
O3 detects CVE-2026-53717 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.