PT-2026-8019 · Unknown · Bacnet Stack

Steve Karg · Published 2026-02-13 · Updated 2026-02-18 · CVE-2026-21878

Positive Technologies (AI Summary)

CVSS v3.1

7.5

High

Base vector

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

Name of the Vulnerable Software and Affected Versions BACnet Stack versions prior to 1.5.0.rc3

Description The BACnet Stack software contains a flaw in its file writing functionality. Specifically, there is a lack of validation for user-supplied file paths, which could allow attackers to write files to arbitrary directories. The affected files are apps/readfile/main.c and ports/posix/bacfile-posix.c.

Recommendations Update to version 1.5.0.rc3 or later.

Exploit

Fix

Path traversal

Weakness Enumeration

CWE-22

Related Identifiers

CVE-2026-21878

GHSA-P8RX-C26W-545J

Affected Products

Bacnet Stack

References · 9

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21878.json · Exploit
• 🔥 https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-p8rx-c26w-545j · Exploit
• https://github.com/bacnet-stack/bacnet-stack/commit/c5dc00a77b4bc2550befa67a930b333e299c18f3 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-21878 · Security Note
• https://osv.dev/vulnerability/CVE-2026-21878 · Vendor Advisory
• https://t.me/CVEtracker/44640 · Telegram Post
• https://twitter.com/cracbot/status/2024076488795107633 · Twitter Post
• https://twitter.com/VulmonFeeds/status/2022404744011034758 · Twitter Post
• https://twitter.com/CVEnew/status/2022387981416567239 · Twitter Post