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  4. CVE 2026 49990 bacnet stack atomicreadfileatomicwritefile stream
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Back to active CVEs
High · CVSS 8.6CVE-2026-49990

BACnet Stack: AtomicReadFile/AtomicWriteFile stream fileStartPosition validation flaw causes out-of-bounds read/write in RAM file backendsCVE-2026-49990

Answer in brief

CVE-2026-49990 records a High severity (CVSS 8.6) vulnerability in BACnet Stack: AtomicReadFile/AtomicWriteFile stream fileStartPosition validation flaw causes out-of-bounds read/write in RAM file backends. The current sources do not mark it as known exploited. The current feed maps bacnet-stack/bacnet-stack (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Nov 13, 2026Updated Nov 13, 2026Source checked Nov 13, 2026First seen by HOL Nov 13, 2026Material review Nov 13, 2026
Upstream Advisory

Key facts

Risk
High · CVSS 8.6
Exploitation
Not marked as known exploited
Affected software
1 mapped package or product
Fix availability
Available

Why this deserves its current priority

CVSS is 8.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps bacnet-stack/bacnet-stack (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
bacnet-stack/bacnet-stackgeneric>=1.4.2 <1.4.5 || >=1.5.0 <1.5.11.4.5, 1.5.1

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for bacnet-stack/bacnet-stack.
  2. 2Review the reported fix. Update bacnet-stack/bacnet-stack to 1.4.5 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Nov 13, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Nov 13, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Nov 13, 2026

Sources and claim methodology

  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • BACnet Stack: Uncontrolled recursion in Timer object writeback path leads to remote server stack overflowSame bacnet-stack/bacnet-stack package
  • BACnet Stack: Global APDU transmit buffer out-of-bounds write in device.address-binding response encoding via address_list_encode()Same bacnet-stack/bacnet-stack package
  • BACnet Stack: Buffer overflows in bsc_node_parse_urls() (BACnet/SC Address Resolution ACK URL parser)Same bacnet-stack/bacnet-stack package
  • BACnet Stack: Denial of Service (Infinite Loop) in handler_read_property_multiple via malformed RPM requestsSame bacnet-stack/bacnet-stack package
  • BACnet Stack: bacnet_device.c stack-use-after-return in writable Device string propertiesSame bacnet-stack/bacnet-stack package
  • BACnet Stack: Out-of-bounds read in BACnet/SC proprietary header-option decode (bvlc_sc_decode_proprietary_option)Same bacnet-stack/bacnet-stack package

Record context

Vulnerability class
Buffer Overflow
EPSS
Not reported
CWE IDs
CWE-125, CWE-787
Source
CVE List V5
Source checked
Nov 13, 2026
References
2 linked sources
Open source record