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Fencer Vulns
medium 5.3

CVE-2026-73549 json

Envoy - Incomplete fix for CVE-2026-26310: copyInternetAddressAndPort crashes on scoped IPv6 addresses in ORIGINAL_DST clusters

published 2026-09-21 48 d ago modified 2026-10-06 33 d ago also BIT-envoy-2026-73549 , EUVD-2026-84108 , GHSA-jp5f-qr64-c9vw

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

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 Utility::copyInternetAddressAndPort and QUIC client-address paths reconstruct scoped IPv6 addresses through addressAsString and Ipv6Instance. The string includes a percent scope identifier that inet_pton cannot parse, causing an exception or abort. Kernel-provided scoped IPv6 destinations in ORIGINAL_DST transparent-proxy deployments, and affected QUIC connection paths, can therefore terminate the process. The relevant scope boundary is that the HTTP use_http_header override rejects scoped addresses earlier; the advisory's crash path requires a kernel-provided original destination or the affected QUIC path. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

Patch / fix

  • bitnami envoy 1.36.10, 1.37.6, 1.38.4, 1.39.1
  • envoyproxy envoy 1.36.10, 1.37.6, 1.38.4, 1.39.1
  • istioctl openSUSE Tumbleweed 1.30.4-1.1

opensuse advisories openSUSE-SU-2026:11630-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-73549 updated cvss 5.3

envoy: envoy: scoped IPv6 handling crash for HTTP/3 clients in original DST clusters

  • Red Hat OpenShift Service Mesh 3.0 openshift-service-mesh/istio-proxyv2-rhel9 1788296328
    fixed: vendor fix RHSA-2026:65106
  • Red Hat OpenShift Service Mesh 3.1 openshift-service-mesh/istio-proxyv2-rhel9 1788294715
    fixed: vendor fix RHSA-2026:65112
  • Red Hat OpenShift Service Mesh 3.2 openshift-service-mesh/istio-proxyv2-rhel9 1788329366
    fixed: vendor fix RHSA-2026:65113
  • Red Hat OpenShift Service Mesh 3.3 openshift-service-mesh/istio-proxyv2-rhel9 1788327866
    fixed: vendor fix RHSA-2026:65115
  • Red Hat OpenShift Service Mesh 3.4 openshift-service-mesh/istio-proxyv2-rhel9 1788333924
    fixed: vendor fix RHSA-2026:65121
  • Red Hat OpenShift Service Mesh 3.0 openshift-service-mesh/istio-cni-rhel9 1788292951, openshift-service-mesh/istio-pilot-rhel9 1788292901, openshift-service-mesh/istio-rhel9-operator 1788292915, openshift-service-mesh/istio-must-gather-rhel9 1788266981, openshift-service-mesh/istio-sail-operator-bundle 1788341233, openshift-service-mesh-dev-preview-beta/istio-ztunnel-rhel9 1788334488 Red Hat OpenShift Service Mesh 3.1 openshift-service-mesh/istio-cni-rhel9 1788294468, openshift-service-mesh/istio-pilot-rhel9 1788294578, openshift-service-mesh/istio-rhel9-operator 1788294534, openshift-service-mesh/istio-must-gather-rhel9 1788271718, openshift-service-mesh/istio-sail-operator-bundle 1788349977, openshift-service-mesh-tech-preview/istio-ztunnel-rhel9 1788334034 Red Hat OpenShift Service Mesh 3.2 openshift-service-mesh/istio-cni-rhel9 1788301003, openshift-service-mesh/istio-pilot-rhel9 1788301006, openshift-service-mesh/istio-ztunnel-rhel9 1788304137, openshift-service-mesh/istio-rhel9-operator 1788301001, openshift-service-mesh/istio-must-gather-rhel9 1788272030, openshift-service-mesh/istio-sail-operator-bundle 1788341754 Red Hat OpenShift Service Mesh 3.3 openshift-service-mesh/istio-cni-rhel9 1788301494, openshift-service-mesh/istio-pilot-rhel9 1788301650, openshift-service-mesh/istio-ztunnel-rhel9 1788286709, openshift-service-mesh/istio-rhel9-operator 1788301636, openshift-service-mesh/istio-must-gather-rhel9 1788262619, openshift-service-mesh/istio-sail-operator-bundle 1788342282 Red Hat OpenShift Service Mesh 3.4 openshift-service-mesh/istio-cni-rhel9 1788333736, openshift-service-mesh/istio-pilot-rhel9 1788333884, openshift-service-mesh/istio-ztunnel-rhel9 1788334411, openshift-service-mesh/istio-rhel9-operator 1788333618, openshift-service-mesh/istio-must-gather-rhel9 1788334442, openshift-service-mesh/istio-sail-operator-bundle 1788347718
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
47 d ago

Exploit prediction

0.62% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami envoy
<1.36.10
>=1.37.0, <1.37.6
>=1.38.0, <1.38.4
>=1.39.0, <1.39.1
1.36.10
1.37.6
1.38.4
1.39.1

Affected products

  • envoyproxy envoy

Classification

Weakness
  • CWE-754 Improper Check for Unusual or Exceptional Conditions

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.