# CVE-2026-62972: BACnet Stack: Out-of-bounds read in lighting_command_decode (full APDU size passed to nested tag decoders)

Status: published. Published: 2026-11-13. Updated: 2026-11-13.

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.5, 1.5.1, and 1.6.0, lighting_command_decode in src/bacnet/lighting.c decodes its first field with the bounded apdu_size - apdu_len, but every nested decode in the operation switch is called with the original full apdu_size while the read pointer has been advanced to &apdu[apdu_len]. The leaf decoders bound their reads against the size they are told, so they read up to apdu_len bytes past the end of the caller's buffer, resulting in an out-of-bounds read. This issue has been patched in versions 1.4.5, 1.5.1, and 1.6.0.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- bacnet-stack / bacnet-stack: < 1.4.5 (affected); < 1.5.1 (affected); < 1.6.0 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-125

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-9hq3-w3pc-8385 (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/bacnet-stack/bacnet-stack/pull/1412 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-62972; retrieved 2026-11-13; source updated 2026-11-13

Revision: 9decd98d1631e15279f408416d018ee7532e233eeb2f4c0abcd296468ec8ab7a

Canonical: https://y2.dev/cve/CVE-2026-62972

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