High 7.5Published Feb 13, 2026

CVE-2026-21878BACnet Stack Improperly Limits Pathnames to a Restricted Directory

Updated under an hour ago (Oct 27, 2026, 7:23 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for bacnet-stack

Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness (CWE): CWE-22
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Feb 13, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

bacnet-stack bacnet-stack bacnet_stack:bacnet_stack (from the name)	before 1.5.0.rc3	CNA record
bacnetstack bacnet_stack bacnetstack:bacnet_stack	1.5.0; 1.5.0	NVD

References

References

https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-p8rx-c26w-545j	x-refsource-confirm, exploit, vendor-advisory
https://github.com/bacnet-stack/bacnet-stack/commit/c5dc00a77b4bc2550befa67a930b333e299c18f3	x-refsource-misc, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.