CVE intelligence

CVE-2026-85091

Vulnerability intelligence

Published Sep 3, 2026Sources checked Sep 12, 2026

7.4HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-85091 and is rated High severity with a CVSS score of 7.4. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

CISA KEVNot listedBased on the latest collected catalog

EPSS0.4%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-85091?

zlib versions 1.3.1.2 through 1.3.2 contain a heap buffer overflow vulnerability in the gz_vacate() function when processing non-blocking gzwrite() operations with stale external buffer pointers. Attackers can trigger the overflow by calling gzprintf() or gzvprintf() after a write stall, causing an unchecked memmove() to write beyond the internal input buffer boundary.