CVE-2026-120457 and is rated Medium severity with a CVSS score of 5.3. 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 4, 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-2026-120457?
libaec through 1.1.7 contains an out-of-bounds read vulnerability in m_se_decode() in src/decode.c that allows attackers to bypass a signed bounds check via an overlong fundamental sequence. Attackers can supply a crafted CCSDS 121.0/SZIP stream with 2^31 or more zero bits to crash the decoder or leak adjacent memory into decoded samples.