CVE-2026-21878 | BDVDB-2026-315342 Detail

bacnet-stackbacnet-stack

Description#

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.5.0.rc3, a vulnerability has been discovered in BACnet Stack's file writing functionality where there is no validation of user-provided file paths, allowing attackers to write files to arbitrary directories. This affects apps/readfile/main.c and ports/posix/bacfile-posix.c. This vulnerability is fixed in 1.5.0.rc3.

Impact#

Per CVSS v3.1: confidentiality impact none, integrity impact high, availability impact none. Attack vector: network.

Weaknesses#

CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

References#

Exploit#

No public exploit known

History#

Version 12026-02-13Record published in the CVE List.

Published

Published: 2026-02-13
Last modified: 2026-02-13

Vendor information

Vendor: bacnet-stack
Product: bacnet-stack

All bacnet-stack vulnerabilities

Score

7.5 High

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 36.9.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Path Traversal

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
< 1.5.0.rc3
Fixed
Not stated

Scoring System

CVSS v4.0

Not available

CVSS v3.1

7.5 High

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

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	None
User Interaction	None
Scope	Unchanged
Confidentiality	None
Integrity	High
Availability	None

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).