Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

Go to Calendar     Go to Press Room     Go to Newsletters subscription

Search

CVE-2026-26309

Severity CVSS v4.0:
Pending analysis
Type:
Unavailable / Other
Publication date:
10/03/2026
Last modified:
11/03/2026

Description

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, an off-by-one write in Envoy::JsonEscaper::escapeString() can corrupt std::string null-termination, causing undefined behavior and potentially leading to crashes or out-of-bounds reads when the resulting string is later treated as a C-string. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

Impact

Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS v3.1 Severity and Metrics:

Base Score: 5.30 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): Low

Base Score 3.x
5.30
Severity 3.x
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* 1.34.13 (excluding)
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* 1.35.0 (including) 1.35.8 (excluding)
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* 1.36.0 (including) 1.36.5 (excluding)
cpe:2.3:a:envoyproxy:envoy:1.37.0:*:*:*:*:*:*:*

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools