CVE-2026-21878
7.5 · HIGHOverview
CVE-2026-21878 is a high-severity vulnerability affecting bacnetstack bacnet_stack. It was published on February 13, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical 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.
Remediation
Check the references section for vendor advisories and patches from bacnetstack. Update bacnet_stack to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
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Frequently Asked Questions
What is CVE-2026-21878?
CVE-2026-21878 is a high-severity vulnerability affecting bacnetstack bacnet_stack. It was published on February 13, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-21878?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-21878?
Check the references section for vendor advisories and patches from bacnetstack. Update bacnet_stack to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-21878?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-21878 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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