CVE-2026-122330 and is rated Medium severity with a CVSS score of 5.5. 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 14, 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-2026-122330?
Blosc c-blosc2 before 3.5.0 contains a divide-by-zero vulnerability in blosc2_schunk_get_slice_buffer() in blosc/schunk.c that allows attackers to crash applications by supplying crafted frames with unchecked zero chunksize or blocksize values. Attackers can provide a malicious Blosc2 frame opened via blosc2_schunk_open() or blosc2_schunk_from_buffer() and read as a slice, raising SIGFPE and terminating the process.