CVSS 3.1
8.6 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:HCVE-2026-49990 BACnet Stack: AtomicReadFile/AtomicWriteFile stream fileStartPosition validation flaw causes out-of-bounds read/write in RAM file backends
High (8.6) in bacnet-stack bacnet-stack.
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BACnet Stack is a BACnet open source protocol stack C library for embedded systems. From versions 1.4.2 to before 1.4.5, and 1.5.0 to before 1.5.1, a signed fileStartPosition taken from AtomicReadFile and AtomicWriteFile stream-access requests is not validated tightly enough before it reaches the RAM file backends. Practical impact includes: reliable denial of service via process crash, out-of-bounds read that may expose adjacent memory contents, or out-of-bounds write that may corrupt heap memory and destabilize the process. This issue has been patched in versions 1.4.5 and 1.5.1.
Severity
- CISA's assessment (SSVC)
- Exploitation: PoC · Automatable: yes · Technical impact: partial, assessed 2026-11-13. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- Published
- Modified
- Assigned by
- GitHub_M (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| bacnet-stack | >= 1.4.2, < 1.4.5 |
| bacnet-stack | >= 1.5.0, < 1.5.1 |
Attack patterns (CAPEC)
- CAPEC-540 Overread Buffers Likelihood: Low · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.