Secuno
ENNL
Book demo

CVE-2026-21878

Bacnetstack Bacnet Stack path traversal

7.5 HIGHPublic exploitEPSS 0.38%
  1. Published13 Feb 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

Bacnetstack Bacnet Stack1.5.0

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

CVE-2026-821109.6
IBM DataStage on Cloud Pak for Data 5.4.0.0 could allow a remote authenticated attacker…
CVE-2026-821019.6
IBM DataStage on Cloud Pak for Data 5.4.0.0 could allow a remote authenticated attacker…
CVE-2026-196278.2
IBM Planning Analytics 2.0, and 2.1 could allow a remote attacker to read arbitrary…
CVE-2026-1026278.8
IBM TRIRIGA Application Platform 5.0.0 through 5.0.8 could allow a remote authenticated…
CVE-2026-599768.1
ConvertX is a self-hosted file conversion service. Prior to 0.18.0, the ImageMagick…
CVE-2026-859538.5
Progress MarkLogic Server 12.x releases before 12.1.0 and 11.x releases before 11.3.7…

Frequently asked

Is CVE-2026-21878 being actively exploited?

CVE-2026-21878 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.38%.

How severe is CVE-2026-21878?

CVE-2026-21878 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.38% probability of exploitation.

Which products are affected by CVE-2026-21878?

Affected products include Bacnetstack Bacnet Stack.

How do I fix CVE-2026-21878?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-21878 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

See how prioritisation worksBook a demo

Get Patch this first every Monday

Five vulnerabilities that matter this week, ranked on real exploitation. Plain language, one email, no spam.

You can unsubscribe with one click from every issue. We handle your details as described in our privacy policy.

Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.