bacnet-stack BACnet Stack up to 1.5.0 FILE object implementation AtomicReadFile PROP_FILE_SIZE uninitialized variable

Summaryinfo

A vulnerability classified as critical was found in bacnet-stack BACnet Stack up to 1.5.0. Affected by this issue is the function AtomicReadFile of the component FILE object implementation. The manipulation of the argument PROP_FILE_SIZE results in uninitialized variable. This vulnerability is reported as CVE-2026-62977. The attack can be launched remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in bacnet-stack BACnet Stack up to 1.5.0. It has been classified as critical. Affected is the function AtomicReadFile of the component FILE object implementation. The manipulation of the argument PROP_FILE_SIZE with an unknown input leads to a uninitialized variable vulnerability. CWE is classifying the issue as CWE-457. The code uses a variable that has not been initialized, leading to unpredictable or unintended results. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to version 1.5.1, the BACnet FILE object implementation allows remote WriteProperty(PROP_FILE_SIZE) requests to change the size of a stream-access FILE object without checking whether that FILE is marked Read_Only. When the FILE backend is RAMFS, enlarging the file only performs realloc() and updates the stored size; the newly exposed tail region is not initialized before later reads. As a result, a remote client can enlarge a read-only RAMFS-backed stream-access FILE and then immediately retrieve the newly exposed region with AtomicReadFile(stream-access). Depending on the allocator and build configuration, the returned data may contain sanitizer fill bytes, stale heap contents, or other unintended process memory. Shrinking the file through the same path can also remotely truncate content that was intended to be read-only. This issue has been patched in versions 1.5.1 and 1.6.0.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-62977 since 07/15/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Technical details are known, but there is no available exploit.

Upgrading to version 1.5.1 eliminates this vulnerability.

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Productinfo

Vendor

• bacnet-stack

Name

• BACnet Stack

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5.0

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CPE 2.2info

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