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VulnerabilityPublished

CVE-2026-73546: envoyproxy envoy · Cross-site Scripting

Affects envoyproxy envoySource CVE Database V5

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Not known to be exploited · CVSS 7.4 High · fixed in 1.39.1 : patch envoyproxy envoy soon.

Data as of 5 Nov 2026, 00:01 UTC

CVSS 3.1 base score
7.4High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.39.1, 1.38.4, 1.37.6 +1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 21 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

What to do

Upgrade envoy and envoyproxy/envoy to 1.39.1, 1.38.4, 1.37.6 or 1.36.10.

Affected software

ProductAffectedFixed in
envoyproxyenvoyAffected
  • >=1.39.0 <1.39.1
Fixed in
  • 1.39.1
envoyproxyenvoyAffected
  • >=1.38.0 <1.38.4
Fixed in
  • 1.38.4
envoyproxyenvoyAffected
  • >=1.37.0 <1.37.6
Fixed in
  • 1.37.6
envoyproxyenvoyAffected
  • <1.36.10
Fixed in
  • 1.36.10
GitHubenvoyproxy/envoypkg:github/envoyproxy/envoyOther threatsAffected
  • <1.36.10
  • >=1.37.0 <1.37.6
  • >=1.38.0 <1.38.4
  • >=1.39.0 <1.39.1
Fixed in
  • 1.36.10
  • 1.37.6
  • 1.38.4
  • 1.39.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

This vulnerability is fixed in Envoy versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1. Users should upgrade to one of these or later versions to remediate the issue. No additional mitigation is indicated by the vendor advisory.

Description

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.

References

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