CVE-2026-53716
Envoy Gateway: Wasm HTTP fetch decompresses gzip without output-size limit
Description
Vulnerability report without repro case. Repro case may be added later after harness is complete. **Preconditions (4):** - Tenant can create EnvoyExtensionPolicy (baseline) - Attacker hosts a gzip-bomb at a reachable URL - sha256 unset (optional field; check is post-decompression anyway) - No operator Wasm-URL allowlist (none exists in code) **Description** getFileFromGZ calls io.ReadAll on a raw gzip.Reader (httpfetcher.go:216) with no output bound, while the compressed input is capped at 256 MiB (httpfetcher.go:139). The bytes originate from a tenant-controlled EnvoyExtensionPolicy.spec.wasm[].code.http.url (envoyextensionpolicy.go:1077 → cache.go:248 → httpfetcher.go:147 → :233), so an untrusted tenant can point at a ~10 MiB gzip-of-zeros and force ~10 GiB allocation in the shared controller process. All candidate guards execute either before the body is buffered or after decompression. OOM-kills, restarts, re-reconciles same CR, crash-loops — persistent cross-tenant control-plane outage with PR:L/AC:L and scope change → HIGH despite availability-only.
How to fix CVE-2026-53716
To remediate CVE-2026-53716, upgrade the affected package to a fixed version below.
- —upgrade to 1.8.1 or later
Is CVE-2026-53716 being exploited?
No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-53716.
Affected packages (1)
- >= 1.8.0-rc.0, < 1.8.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |