CVE-2026-26309

MEDIUM

Envoy < 1.37.1, 1.36.5, 1.35.8, 1.34.13 - Off-by-one Write in JsonEscaper

Title source: llm
STIX 2.1

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.

References (1)

Core 1
Core References

Scores

CVSS v3 5.3
EPSS 0.0037
EPSS Percentile 28.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-193
Status published
Products (2)
envoyproxy/envoy 1.37.0
envoyproxy/envoy < 1.34.13
Published Mar 10, 2026
Tracked Since Mar 11, 2026