# CVE-2026-124760: Alarm receiver stops delivering alarms after a malformed alarm notification

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

P-Net before 1.0.4 sets the alarm receiver state to waiting for confirmation before the data of a received alarm notification is parsed. If the parsing fails the state is not restored, and later alarm notifications of the same priority are discarded without acknowledge until the Application Relationship is released. The Application Relationship and the cyclic data exchange keep working. The attacker must be able to send an alarm notification in the context of an established Application Relationship and requires ADJACENT network access.

## Remediation

- fix: Upgrade to P-Net 1.0.4 or later. (source: CNA: rt-labs)

## Affected products and versions

- RT-Labs / P-Net: ≥ 0; < 1.0.4 (affected, semver). Source: CNA: rt-labs

## Severity and prioritization

- CVSS 4.0: 2.3 (low); CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N; source: CNA: rt-labs

- CVSS 4.0: 2.3 (low); CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: 4b71179a-3b92-4a9d-b9fc-af8b8ed579ee

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-754

## Exploit evidence

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

## References

- https://rt-labs.com/wp-content/uploads/2026/11/RRTL-261109-01.pdf (CNA: rt-labs)

- https://rt-labs.com/wp-content/uploads/2026/11/RRTL-261109-01.pdf (4b71179a-3b92-4a9d-b9fc-af8b8ed579ee)

## Provenance

- CNA: rt-labs: https://www.cve.org/CVERecord?id=CVE-2026-124760; retrieved 2026-11-13; source updated 2026-11-13

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-124760; retrieved 2026-11-13; source updated 2026-11-13

Revision: 4dbf82e44dcd52b02b78e7318094e7bbe32210f3775a46a23b388ed452a2e0e0

Canonical: https://y2.dev/cve/CVE-2026-124760

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