Published Nov 10, 2026Sources checked Nov 14, 2026
4.2MEDIUMCVSS out of 10
What this means
Review the available evidence
CVE-2026-125709 and is rated Medium severity with a CVSS score of 4.2. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
What to do next
Remediation and response
Microsoft Security Response Center guidance
Vendor revision: Nov 13, 2026
Release Notes
CISA KEVNot listedBased on the latest collected catalog
EPSS0.2%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-125709?
A flaw was found in libstdc++. When a byte-by-byte write operation fails during file stream processing, the library may still append data into the internal memory buffer.
An attacker capable of inducing repeated write failures in an affected service can trigger a buffer overflow, potentially resulting in a Denial of Service (DoS) or memory corruption.