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Fencer Intel
high 7.5

CVE-2026-100403 json

BACnet Stack: BACnet/SC hub grows its WebSocket reassembly buffer without limit, so a peer can exhaust its memory

published last mo. modified yesterday also EUVD-2026-125694 , GHSA-4vgv-v5ph-rmxr

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository bacnet-stack/bacnet-stack. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.6, 1.5.2, and 1.6.1, the BACnet/SC hub's Linux WebSocket server reassembles fragmented WebSocket messages into a per-connection fragment_buffer. It grows that buffer with realloc() on every non-final frame, with no upper bound. A peer that streams binary continuation fragments and never sets FIN keeps the hub reallocating until the box runs out of memory or the process is OOM-killed. The buffer starts at the maximum legal BVLC-SC NPDU size, but nothing after that ties its growth back to that limit. This issue has been patched in versions 1.4.6, 1.5.2, 1.6.1, and 1.7.0.

Patch / fix

Is CVE-2026-100403 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-14).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • bacnet-stack bacnet-stack

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of bacnet-stack/bacnet-stack published their own advisory on GitHub. Reviewed sources take precedence over it.