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CVE-2026-73549

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

MEDIUM
5.3
CVSS Score
Published: September 21, 2026 at 07:42 PM UTC
Updated: October 5, 2026 at 02:09 PM UTC
1 product affected across 1 vendorEnvoy

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

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 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Envoy· Envoyproxy
95%
v < 1.36.10v < 1.37.6v < 1.38.4v < 1.39.11.37.0 ≤ v < 1.37.61.38.0 ≤ v < 1.38.41.39.0 ≤ v < 1.39.1
Affected range stops below 1.36.10, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.37.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.38.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.39.1, so it looks safe — our inference, not a vendor statement

References (9)

x_refsource_CONFIRMVendor AdvisoryMitigation
Source: cverecord
https://github.com/envoyproxy/envoy/security/advisories/GHSA-jp5f-qr64-c9vw
x_refsource_MISCPatch
Source: cverecord
https://github.com/envoyproxy/envoy/commit/109e5a5b08ad10d99074cefd55a747a16ee64da7
x_refsource_MISCPatch
Source: cverecord
https://github.com/envoyproxy/envoy/commit/59b1744a6cb62746db418ac06fc5e359fd25fdb7
x_refsource_MISCPatch
Source: cverecord
https://github.com/envoyproxy/envoy/commit/6e39f4c94deff7a60d382c2d95883e0ea49ff691
x_refsource_MISCPatch
Source: cverecord
https://github.com/envoyproxy/envoy/commit/ab2dca2d65b079768230a7c3d825afeefa330215
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/envoyproxy/envoy/releases/tag/v1.36.10
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/envoyproxy/envoy/releases/tag/v1.37.6
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/envoyproxy/envoy/releases/tag/v1.38.4

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-754

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