CVE-2023-35943

Envoy vulnerable to CORS filter segfault when origin header is removed

HIGH

7.5

CVSS Score

Published: July 25, 2023 at 06:26 PM UTC

Updated: June 17, 2026 at 06:05 AM UTC

1 product affected across 1 vendorEnvoy

Using envoy by envoyproxy?

Get instant alerts when new vulnerabilities affect envoy - before attackers find them.

Real-time alertsTrack your software stackFree plan available

Start Free Sign In

Severity

HIGH7.5

Exploit prediction

EPSS 0.7%

SSVC

PoC

Description

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12, the CORS filter will segfault and crash Envoy when the `origin` header is removed and deleted between `decodeHeaders`and `encodeHeaders`. Versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12 have a fix for this issue. As a workaround, do not remove the `origin` header in the Envoy configuration.

Affected

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

Envoy · Envoyproxy

95%

v < 1.23.12v < 1.24.10v < 1.25.9v < 1.26.41.23.0 ≤ v < 1.23.121.24.0 ≤ v < 1.24.101.25.0 ≤ v < 1.25.91.26.0 ≤ v < 1.26.4

Affected range stops below 1.23.12, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.24.10, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.25.9, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.26.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

x_refsource_CONFIRMExploitThird Party Advisory

Source: [email protected]

https://github.com/envoyproxy/envoy/security/advisories/GHSA-mc6h-6j9x-v3gq

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

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

CVSS

7.5HIGH[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: NONE
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-416

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Create account Sign in

Free plan, no card