Off-by-one in envoy - CVE-2026-26309
Published: August 26, 2026
Vulnerability identifier: #VU145845
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-26309
CWE-ID: CWE-193
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to an off-by-one write in JsonEscaper::escapeString() when processing input. A remote attacker can send crafted input to cause a denial of service.
Affected software
envoy
How to mitigate CVE-2026-26309
Install security update from vendor's website.
envoy - addressed in versions 1.34.13, 1.35.9, 1.36.5, 1.37.1