Vulnerability record/PUBLISHED/Published Nov 13, 2026 15:54:22 UTC

CVE-2026-49990

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. From versions 1.4.2 to before 1.4.5, and 1.5.0 to before 1.5.1, a signed fileStartPosition taken from AtomicReadFile and AtomicWriteFile stream-access requests is not validated tightly enough before it reaches the RAM file backends. Practical impact includes: reliable denial of service via process crash, out-of-bounds read that may expose adjacent memory contents, or out-of-bounds write that may corrupt heap memory and destabilize the process. This issue has been patched in versions 1.4.5 and 1.5.1.

Base score8.6/ 10

SeverityHighCVSS 3.1

Exploitability / impact

CVSS metric breakdown

Vector-derived attributes

Base severityHigh

Attack vectorNetworkAV

Attack complexityLowAC

Privileges requiredNonePR

User interactionNoneUI

ScopeUnchangedS

Confidentiality impactLowC

Integrity impactLowI

Availability impactHighA

CVSS vector stringCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

CVSS communicates standardized severity and impact characteristics. It does not establish whether a system is exploitable in your specific environment.

Record context

CVE Numbering AuthorityGitHub_M

Last updatedNov 13, 2026 15:54:22 UTC

PublishedNov 13, 2026 15:54:22 UTC

ReservedJun 2, 2026 18:30:51 UTC