CVE-2026-21870: The BACnet Protocol Stack library has an Off-by-one Stack-based Buffer Overflow in tokenizer_string
Affected: bacnet-stack · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 19% of scored CVEs
DescriptionCVE.org
BACnet Protocol Stack library provides a BACnet application layer, network layer and media access (MAC) layer communications services. In 1.4.2, 1.5.0.rc2, and earlier, an off-by-one stack-based buffer overflow in the ubasic interpreter causes a crash (SIGABRT) when processing string literals longer than the buffer limit. The tokenizer_string function in src/bacnet/basic/program/ubasic/tokenizer.c incorrectly handles null termination for maximum-length strings. It writes a null byte to dest[40] when the buffer size is only 40 (indices 0-39), triggering a stack overflow.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- bacnet-stack · bacnet-stack<= 1.4.2; >= 1.5.0.rc1, <= 1.5.0.rc2
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- bacnet-stack
- Published
- February 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-21870 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.