# CVE-2026-111735: P-Net integer underflow in pf_cpm_c_data_ind()

Source: https://junglewise.ai/threats/cve-2026-111735-p-net-before-1-0-3-contains-an-integer-underflow-in-pf-cpm-c  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-29. Updated: 2026-10-29  
License: CC BY 4.0 with a link back

CVE-2026-111735 · Severity: info · Published 2026-10-29

P-Net is an industrial protocol library used in manufacturing and automation systems. A flaw in its cyclic data frame handler allows an attacker on the network to send a specially crafted short frame that causes the software to read from invalid memory locations, leading to crashes or exposure of sensitive data in memory.

Technologies: [RT-Labs P-Net](https://junglewise.ai/threats/technologies/p-net). Vendors: [RT-Labs](https://junglewise.ai/threats/vendors/rt-labs).

## Quick answers

**Is CVE-2026-111735 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-111735 being exploited in the wild.

**How severe is CVE-2026-111735?** Informational severity, published 29 October 2026.

**Which products and versions are affected?** RT-Labs P-Net before 1.0.3.

**Is there a fix for CVE-2026-111735?** Yes: fixed in P-Net 1.0.3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-111735 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-111735?** Check whether you run RT-Labs P-Net 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.

## How to fix

- Fixed in P-Net 1.0.3

## Technical details

The pf_cpm_c_data_ind() function computes an APDU status offset using 16-bit subtraction (frame_length - 4) without validating that the frame is sufficiently long, causing an integer underflow when frames shorter than 4 bytes are processed. An attacker sending a malicious cyclic data frame while the consumer is in FRUN or RUN state triggers out-of-bounds memory reads, enabling denial of service or information disclosure.

## Affected products

- rt-labs P-Net before 1.0.3

## Timeline

- 2026-10-29: disclosed

## References

- [https://rt-labs.com/wp-content/uploads/2026/10/RRTL-261019-01.pdf](https://rt-labs.com/wp-content/uploads/2026/10/RRTL-261019-01.pdf)

## Related threats

- [P-Net buffer over-read in DCP message processing](https://junglewise.ai/threats/cve-2026-115795-p-net-before-1-0-3-does-not-check-that-a-complete-block-header)
- [P-Net buffer over-read in RTA alarm callback](https://junglewise.ai/threats/cve-2026-115794-p-net-before-1-0-3-passes-the-application-alarm-callback-a-data)
- [P-Net RPC session leak leading to denial of service](https://junglewise.ai/threats/cve-2026-115793-p-net-before-1-0-3-does-not-release-the-rpc-session-allocated)
- [P-Net resource exhaustion via malformed RPC requests](https://junglewise.ai/threats/cve-2026-112200-p-net-before-1-0-3-does-not-release-the-application-relationship)
- [P-Net NULL pointer dereference in implicit read request handling](https://junglewise.ai/threats/cve-2026-111736-p-net-before-1-0-3-dereferences-a-null-ar-pointer-in-pf-fspm-cm)