Envoy’s TLS certificate matcher for `match_typed_subject_alt_names` may incorrectly treat…
Priority MEDIUM 64CWE-170Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · Low · None
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA, GitHub and Red Hat.
Summary
Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, Envoy’s mTLS certificate matcher for match_typed_subject_alt_names may incorrectly treat certificates containing an embedded null byte (\0) inside an OTHERNAME SAN value as valid matches.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0018 7th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial github.com/envoyproxy/envoy (Go): 1.36.3, 1.35.7, 1.34.11 +1Red Hat: 1 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| envoyproxy | envoy | 1.36.0 – 1.36.2; 1.35.0 – 1.35.6; 1.34.0 – 1.34.10; up to 1.33.12 | — | No fix listed | CNA |
| — | github.com/envoyproxy/envoy (Go) | 1.36.0 to before 1.36.3 | 1.36.3 | Patch available | GHSA-rwjg-c3h2-f57p |
| — | github.com/envoyproxy/envoy (Go) | 1.35.0 to before 1.35.7 | 1.35.7 | Patch available | GHSA-rwjg-c3h2-f57p |
| — | github.com/envoyproxy/envoy (Go) | 1.34.0 to before 1.34.11 | 1.34.11 | Patch available | GHSA-rwjg-c3h2-f57p |
| — | github.com/envoyproxy/envoy (Go) | before 1.33.13 | 1.33.13 | Patch available | GHSA-rwjg-c3h2-f57p |
- envoy Vendorenvoyproxy Affected 1.36.0 – 1.36.2; 1.35.0 – 1.35.6; 1.34.0 – 1.34.10; up to 1.33.12 Fixed in — No fix listed CNA
- github.com/envoyproxy/envoy (Go) Vendor— Affected 1.36.0 to before 1.36.3 Fixed in 1.36.3 Patch available GHSA-rwjg-c3h2-f57p
- github.com/envoyproxy/envoy (Go) Vendor— Affected 1.35.0 to before 1.35.7 Fixed in 1.35.7 Patch available GHSA-rwjg-c3h2-f57p
- github.com/envoyproxy/envoy (Go) Vendor— Affected 1.34.0 to before 1.34.11 Fixed in 1.34.11 Patch available GHSA-rwjg-c3h2-f57p
- github.com/envoyproxy/envoy (Go) Vendor— Affected before 1.33.13 Fixed in 1.33.13 Patch available GHSA-rwjg-c3h2-f57p
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* | before 1.33.13; 1.34.0 to before 1.34.11; 1.35.0 to before 1.35.7; 1.36.0 to before 1.36.3 | Vulnerable | envoyproxy |
- cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* Versions before 1.33.13; 1.34.0 to before 1.34.11; 1.35.0 to before 1.35.7; 1.36.0 to before 1.36.3 Vulnerable ·envoyproxy
Remediation
- Fix · GHSA-rwjg-c3h2-f57p github.com/envoyproxy/envoy (Go) Fixed in 1.36.3 Advisory →
- Fix · GHSA-rwjg-c3h2-f57p github.com/envoyproxy/envoy (Go) Fixed in 1.35.7 Advisory →
- Fix · GHSA-rwjg-c3h2-f57p github.com/envoyproxy/envoy (Go) Fixed in 1.34.11 Advisory →
- Fix · GHSA-rwjg-c3h2-f57p github.com/envoyproxy/envoy (Go) Fixed in 1.33.13 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| OpenShift Service Mesh 3 | Affected | No fix yet |
Not affected: 2 products
- OpenShift Service Mesh 2
- OpenShift Service Mesh 3
Timeline
- 2026-10-02 Threatist record created from CVE-2025-66220
- 2026-10-03 Alias added: GHSA-rwjg-c3h2-f57p
References
More envoyproxy Envoy vulnerabilities
- TI-2026-79288 Out-of-bounds write in Google Brotli decoder KEVCVSS 4.0CRITICAL 9.2
- TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
- TI-2024-20001 HTTP/2: CPU exhaustion due to CONTINUATION frame flood CVSS 3.1HIGH 7.5
- TI-2024-18524 HTTP/2: memory exhaustion due to CONTINUATION frame flood CVSS 3.1HIGH 7.5
- TI-2023-12215 Envoy client may fake the header `x-envoy-original-path` CVSS 3.1CRITICAL 9.1
- TI-2023-18002 Envoy vulnerable to OAuth2 credentials exploit with permanent validity CVSS 3.1CRITICAL 9.8
Sources
- CVE-2025-66220 · CVE Program
- CVE-2025-66220 · NVD
- FIRST EPSS
- GHSA-rwjg-c3h2-f57p · GitHub Advisory Database · CC BY 4.0
- CVE-2025-66220 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences