Vulnerability · CVE-2026-26264
BACnet Stack is a BACnet open source protocol stack C library for embedded systems.
Published Feb 13, 2026 · catalog updated Feb 13, 2026 · BACnet Stack is a
Last checked Nov 3, 2026. A connected source was read within the last 7 days.
Check if you run it
No confirmed exploitation is on record for CVE-2026-26264. EPSS is 0.43%. Act only if a listed version of BACnet Stack is a is installed.
Gaps on this record
- The stored product name is a package slug. The name on this page is taken from the title (BACnet Stack is a).
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
Same product and reporting
- CVE-2026-21878 · High
- CVE-2026-21870 · Medium
- CVE-2025-66624 · High
- Severity
- High7.8
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.43%
- Remediation
- Version ranges on file
- Affected products
- vendor bacnet-stack bacnet-stack 1.5.0rc1, < 1.5.0rc4
BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.5.0rc4 and 1.4.3rc2, a malformed WriteProperty request can trigger a length underflow in the BACnet stack, leading to an out‑of‑bounds read and a crash (DoS). The issue is in wp.c within wp_decode_service_request. When decoding the optional priority context tag, the code passes apdu_len - apdu_size to bacnet_unsigned_context_decode without validating that apdu_size <= apdu_len. If a truncated APDU reaches this path, apdu_len - apdu_size underflows, resulting in a large size being used for decoding an
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- vendor bacnet-stack bacnet-stack 1.5.0rc1, < 1.5.0rc41.5.0rc1, < 1.5.0rc4
How to fix CVE-2026-26264
Upgrade
CVE-2026-26264 lists a fix boundary at 1.5.0rc4. Compare the installed build with that boundary before you change production.
Version check
Affected < 1.5.0rc4
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-26264. EPSS is 0.43%. Act only if a listed version of BACnet Stack is a is installed.
Which versions are affected?
Compare what you have installed with bacnet-stack bacnet-stack 1.5.0rc1, < 1.5.0rc4 1.5.0rc1, < 1.5.0rc4. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
No weakness class is stored. EPSS 0.43%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Feb 13, 2026 · EUVD
Detected
BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.5.0rc4 and 1.4.3rc2, a malformed WriteProperty request can trigger a length underflow in the BACnet stack, leading to an out‑of‑bounds read and a crash (DoS). The issue is in wp.c within wp_decode_service_request. When decoding the optional priority context tag, the code passes apdu_len - apdu_size to ba
Feb 13, 2026 · EUVD
Updated
BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.5.0rc4 and 1.4.3rc2, a malformed WriteProperty request can trigger a length underflow in the BACnet stack, leading to an out‑of‑bounds read and a crash (DoS). The issue is in wp.c within wp_decode_service_request. When decoding the optional priority context tag, the code passes apdu_len - apdu_size to ba
Sources
- FIRST EPSSExploitation probabilityCVE-2026-26264
30-day exploitation probability 0.43%
first.org - EUVDVulnerability recordEUVD-2026-6027
BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.5.0rc4 and 1.4.3rc2, a malformed WriteProperty request can trigger a length underflow in the BACnet stack, leading to an out‑of‑bounds read and a crash (DoS). The issue is in wp.c withi
euvd.enisa.europa.eu
References
Freshness
Last verified in this catalog Nov 3, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.
- FIRST EPSSNov 3, 2026
- EUVDNov 3, 2026