bacnet-stack BACnet Stack up to 1.4.4/1.5.0 RAM file backend AtomicReadFile/AtomicWriteFile fileStartPosition out-of-bounds write

Summaryinfo

A vulnerability marked as critical has been reported in bacnet-stack BACnet Stack up to 1.4.4/1.5.0. Affected is the function AtomicReadFile/AtomicWriteFile of the component RAM file backend. This manipulation of the argument fileStartPosition causes out-of-bounds write. This vulnerability is handled as CVE-2026-49990. The attack can be initiated remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability has been found in bacnet-stack BACnet Stack up to 1.4.4/1.5.0 and classified as critical. Affected by this vulnerability is the function AtomicReadFile/AtomicWriteFile of the component RAM file backend. The manipulation of the argument fileStartPosition with an unknown input leads to a out-of-bounds write vulnerability. The CWE definition for the vulnerability is CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-49990 since 06/02/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available.

Upgrading to version 1.4.5 or 1.5.1 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• bacnet-stack

Name

• BACnet Stack

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.4.0
• 1.4.1
• 1.4.2
• 1.4.3
• 1.4.4
• 1.5.0

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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