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Vulnerabilities

Vulnerability · CVE-2025-64763

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 Nov 3, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-64763. EPSS is 0.32%. 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
Low3.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.32%
Remediation
Advisory link
Affected products
vendor envoyproxy envoy 1.34.0, ≤ 1.34.10

Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, when Envoy is configured in TCP proxy mode to handle CONNECT requests, it accepts client data before issuing a 2xx response and forwards that data to the upstream TCP connection. If a forwarding proxy upstream from Envoy then responds with a non-2xx status, this can cause a de-synchronized CONNECT tunnel state. By default Envoy continues to allow early CONNECT data to avoid disrupting existing deployments. The envoy.reloadable_features.reject_early_connect_data runtime flag can be set to re

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 1.34.0, ≤ 1.34.101.34.0, ≤ 1.34.10

How to fix CVE-2025-64763

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-2025-64763. EPSS is 0.32%. 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 1.34.0, ≤ 1.34.10 1.34.0, ≤ 1.34.10. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.32%. 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, when Envoy is configured in TCP proxy mode to handle CONNECT requests, it accepts client data before issuing a 2xx response and forwards that data to the upstream TCP connection. If a forwarding proxy upstream from Envoy then responds with a non-2xx status, this can cause a de-synchronized CONN

  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, when Envoy is configured in TCP proxy mode to handle CONNECT requests, it accepts client data before issuing a 2xx response and forwards that data to the upstream TCP connection. If a forwarding proxy upstream from Envoy then responds with a non-2xx status, this can cause a de-synchronized CONN

Sources

  • CVE.orgVulnerability recordCVE-2025-64763

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-64763

    30-day exploitation probability 0.32%

    first.org
  • EUVDVulnerability recordEUVD-2025-201099

    Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, when Envoy is configured in TCP proxy mode to handle CONNECT requests, it accepts client data before issuing a 2xx response and forwards that data to the upstream TCP connecti

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 3, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 3, 2026
  • CVE.orgOct 28, 2026
  • EUVDOct 27, 2026