# CVE-2026-84235: Rockwell Automation 1756-ENBT denial of service in CIP packet handling

Source: https://junglewise.ai/threats/cve-2026-84235-rockwell-automation-1756-enbt-denial-of-service-in-cip-packet  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-01. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-84235 · Severity: info · CVSS 8.7 · Published 2026-09-01

The Rockwell Automation 1756-ENBT module is an EtherNet/IP bridge used in industrial automation systems to connect ControlLogix controllers to Ethernet devices. A vulnerability allows an attacker to send a specially crafted CIP (Common Industrial Protocol) packet that crashes the module, forcing a manual restart and disrupting production operations. No patch is currently available.

Vendors: [Rockwell Automation](https://junglewise.ai/threats/vendors/rockwell-automation).

## Quick answers

**Is CVE-2026-84235 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-84235 being exploited in the wild.

**How severe is CVE-2026-84235?** Informational severity, with a CVSS score of 8.7, published 1 September 2026.

**Which products and versions are affected?** Rockwell Automation 1756-ENBT all versions; Rockwell Automation 1756-EWEB all versions; Rockwell Automation L3xX all versions.

**Is there a fix for CVE-2026-84235?** No fixed version is recorded yet. Check the vendor's advisory in the references below. 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-2026-84235 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-84235?** Check whether you run Rockwell Automation 1756-ENBT, Rockwell Automation 1756-EWEB or Rockwell Automation L3xX 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

This is a denial-of-service vulnerability in the CIP packet parsing logic of the 1756-ENBT module. A remote attacker can send a malformed CIP packet over the network to trigger a crash in the affected device, which requires manual intervention to restart. The vulnerability affects all firmware versions of the 1756-ENBT, 1756-EWEB, and L3xX catalog numbers. No permanent fix has been released; Rockwell Automation recommends upgrading to the 1756-EN2T or 1756-EN4TR modules as a replacement, or implementing network-based security controls as a workaround.

## Affected products

- Rockwell Automation 1756-ENBT all versions
- Rockwell Automation 1756-EWEB all versions
- Rockwell Automation L3xX all versions

## Timeline

- 2026-09-01: disclosed
- 2026-09-01: advisory: Rockwell Automation SD1798

## References

- [https://www.rockwellautomation.com/en-us/trust-center/security-advisories/advisory.SD1798.html](https://www.rockwellautomation.com/en-us/trust-center/security-advisories/advisory.SD1798.html)

## Related threats

- [Rockwell Automation 1756-EN series denial of service in CIP packets](https://junglewise.ai/threats/cve-2026-9653-rockwell-automation-1756-en-series-denial-of-service-in-cip)