XSS in Envoyproxy Envoy
CVE-2026-73546
Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy's /stats?format=html admin endpoint uses StatsHtmlRender, which sanitizes string statistic values but emits statistic names without HTML encoding. A data-plane component such as grpc_stats with stats_for_all_methods enabled can incorporate attacker-controlled path segments into cached dynamic statistic names. When an operator views the HTML stats page, the stored name can execute script with the admin interface's origin and issue privileged same-origin requests. The relevant scope boundary is that the admin interface must be browser-accessible and an enabled component must persist attacker-influenced text in statistic names. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.
Vulnerability class: XSS (Cross-Site Scripting)
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.
Affected products
- Envoyproxy Envoy — versions < 1.36.10, >= 1.37.0, < 1.37.6, >= 1.38.0, < 1.38.4
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-73546?
- CVE-2026-73546 is a high-severity vulnerability in Envoyproxy Envoy, classified under Cross-site Scripting. CVSS score: 7.4/10. Published 2026-09-21.
- How severe is CVE-2026-73546?
- High severity. CVSS v3 base score is 7.4 out of 10.