CVE-2026-62977

6.9 MEDIUM Fix listed Auth & access Device

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-07-14 22:48 UTC ReservedThe CVE id was reserved by its CNA
2026-11-13 19:19 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-11-13 22:11 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: not scored yet.
Severity: 6.9 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-11-13 19:19 UTC
Last modified: 2026-11-13 22:11 UTC
Weakness: CWE-284 · Improper access control
Record status: Awaiting Analysis

Attack profile CVSS 4.0 · 6.9

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: None
User interaction: None
Confidentiality: Low
Integrity: Low
Availability: None

Raw vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-62977.md and follow it. Check whether this project is affected by CVE-2026-62977. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record