CVE-2026-55732: Loytec BACnet devices out-of-bounds read in bacdt_datetime_to_tod

CVE-2026-55732 · Severity: info · CVSS 8.7 · Published 2026-07-24

Loytec building automation and control devices are vulnerable to a remote attack that can cause them to crash and reboot. By sending a specially crafted network packet, an unauthenticated attacker can disrupt core building services, leading to a denial of service. This affects various automation servers, touch panels, and lighting controllers used in commercial building management.

Technologies: LOYTEC L-DALI, LOYTEC L-GATE, LOYTEC L-INX, LOYTEC L-IOB, LOYTEC L-PAD, LOYTEC L-ROC, LOYTEC L-VIS, LOYTEC LIP-ME201C. Vendors: LOYTEC.

Quick answers

Is CVE-2026-55732 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-55732 being exploited in the wild.
How severe is CVE-2026-55732?
Informational severity, with a CVSS score of 8.7, published 24 July 2026.
Which products and versions are affected?
LOYTEC L-DALI through 8.4.18; LOYTEC L-GATE through 8.4.18; LOYTEC L-INX through 8.4.18; LOYTEC L-IOB through 8.4.18; and 4 more.
Is there a fix for CVE-2026-55732?
A patch was published on 2026-07-24: Firmware version 8.4.20 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-55732 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-55732?
Check whether you run LOYTEC L-DALI, LOYTEC L-GATE, LOYTEC L-INX or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An out-of-bounds read vulnerability (CWE-125) exists in the BACnet packet parsing component of multiple Loytec products. The flaw is located in the `bacdt_datetime_to_tod` function, where an invalid month value in a BACnet TimeSynchronization or UTC-TimeSynchronization packet triggers an out-of-bounds read against the `bacdt_days_till_month` lookup table. This causes the `linx_a64.exe` process to crash. Because this process provides core services, repeated crashes lead to a full device reboot. The vulnerability is exploitable over the network without authentication. Firmware version 8.4.20 has been released to mitigate this issue.

Affected products

  • Loytec LIP-ME201C through 8.4.18
  • Loytec L-INX through 8.4.18
  • Loytec L-GATE through 8.4.18
  • Loytec L-ROC through 8.4.18
  • Loytec L-IOB through 8.4.18
  • Loytec L-DALI through 8.4.18
  • Loytec L-VIS through 8.4.18
  • Loytec L-PAD through 8.4.18

Timeline

  • 2026-07-24: advisory: NVD and vendor advisory published
  • 2026-07-24: patched: Firmware version 8.4.20 released

References

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