Envoy Gateway: Wasm HTTP fetch decompresses gzip without output-size limit

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-53716: 0.71% estimated exploitation activity in the next 30 days; percentile 53.78 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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…

Published by the source

16 Jul 2026, 19:18 UTC

Last modified by the source

16 Jul 2026, 19:18 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-cxpq-8v7q-cg56

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# Patch Next advisory brief: CVE-2026-53716

Advisory: Envoy Gateway: Wasm HTTP fetch decompresses gzip without output-size limit
IDs: CVE-2026-53716, GHSA-cxpq-8v7q-cg56
Record: https://patchnext.com/advisories/cve-2026-53716 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/envoyproxy/gateway 1.8.1, 1.7.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/envoyproxy/gateway: affected >= 1.8.0-rc.0, < 1.8.1; < 1.7.4; fixed in 1.8.1, 1.7.4

## Suggested inspection (read-only)
- Go github.com/envoyproxy/gateway: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/envoyproxy/gateway.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-cxpq-8v7q-cg56 (GitHub-reviewed advisory GHSA-cxpq-8v7q-cg56 lists affected ranges: Go github.com/envoyproxy/gateway >=1.8.0-rc.0 =0 <1.7.4)

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