# CVE-2026-111732: P-Net out-of-bounds write in ARVendorBlock parsing

Source: https://junglewise.ai/threats/cve-2026-111732-p-net-before-1-0-3-when-built-with-pnet-option-ar-vendor-blocks  
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-2026-111732 · Severity: info · Published 2026-10-29

P-Net is a real-time communication library used in industrial automation systems. A flaw in how it parses vendor-specific data blocks can be exploited to write data beyond the bounds of a memory buffer, potentially crashing the application or allowing an attacker to execute arbitrary code when a malicious Connect request is received.

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-2026-111732 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-111732 being exploited in the wild.

**How severe is CVE-2026-111732?** 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-2026-111732?** No fixed version is recorded yet. Ensure the PNET_OPTION_AR_VENDOR_BLOCKS compile option remains disabled unless vendor block support is explicitly required. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-111732 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-111732?** 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


Ensure the PNET_OPTION_AR_VENDOR_BLOCKS compile option remains disabled unless vendor block support is explicitly required.

## Technical details

The vulnerability is an out-of-bounds write in the ARVendorBlock request handler when PNET_OPTION_AR_VENDOR_BLOCKS is enabled (disabled by default). The parser reads a data length field from the request that is outside the block definition and uses this untrusted length value directly in a memory copy operation without validating it against the buffer size or block length, leading to a buffer overflow.

## 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)