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Vulnerabilities

Vulnerability · CVE-2025-66220

Envoy is a high-performance edge/middle/service proxy.

Published Dec 3, 2025 · catalog updated Dec 3, 2025 · Envoy is a high-performance

Last checked Oct 28, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-66220. EPSS is 0.17%. Act only if a listed version of Envoy is a high-performance is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Envoy is a high-performance).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium5.0
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.17%
Remediation
Advisory link
Affected products
vendor envoyproxy envoy ≤ 1.33.12

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor envoyproxy envoy ≤ 1.33.12≤ 1.33.12

How to fix CVE-2025-66220

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-66220. EPSS is 0.17%. Act only if a listed version of Envoy is a high-performance is installed.

Which versions are affected?

Compare what you have installed with envoyproxy envoy ≤ 1.33.12 ≤ 1.33.12. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.17%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 3, 2025 · EUVD

    Detected

    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.

  2. Dec 3, 2025 · EUVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2025-66220

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-66220

    30-day exploitation probability 0.17%

    first.org
  • EUVDVulnerability recordEUVD-2025-201090

    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 va

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 28, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 28, 2026
  • CVE.orgOct 28, 2026
  • EUVDOct 27, 2026