# CVE-2025-51677: openRISC OR1200 data mismatch in Load-Store Unit debugging interface

Source: https://junglewise.ai/threats/cve-2025-51677-openrisc-or1200-data-mismatch-in-load-store-unit-debugging  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-17. Updated: 2026-07-17  
License: CC BY 4.0 with a link back

CVE-2025-51677 · Severity: info · CVSS 0 · Published 2026-07-17

A technical issue was identified in the openRISC OR1200 processor, a hardware design used in various embedded systems. During debugging operations, the processor may fail to correctly retrieve data from memory, leading to incorrect information being sent to the debugging tools. This can prevent engineers from accurately diagnosing system issues and could lead to unpredictable behavior during system maintenance or analysis.

Technologies: [OpenRISC OR1200](https://junglewise.ai/threats/technologies/or1200). Vendors: [OpenRISC](https://junglewise.ai/threats/vendors/openrisc).

## Quick answers

**Is CVE-2025-51677 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-51677 being exploited in the wild.

**How severe is CVE-2025-51677?** Informational severity, with a CVSS score of 0, published 17 July 2026.

**Which products and versions are affected?** OpenRISC OR1200 commit 83ac6b42d73f00daa88a996a1f6738d5a639a105.

**Is there a fix for CVE-2025-51677?** 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-2025-51677 attacked?** It is attacked with local access, in device firmware.

**Am I affected by CVE-2025-51677?** Check whether you run OpenRISC OR1200 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

A synthesis bug exists in the front-end design of the OR1200 processor, specifically affecting the interface between the Load-Store Unit (LSU) and the Debug Unit. When the Debug Unit requests a memory load operation, the LSU may fail to fully retrieve or provide the requested data, resulting in an 'unknown' (xxxxxxxx) value at the du_lsu_load_dat output port. This discrepancy between the Register Transfer Level (RTL) description and the synthesized gate-level netlist causes a misinterpretation of memory states. The vulnerability was identified using SynFuzz, a differential fuzzing tool designed to detect bugs introduced during the hardware synthesis process. An attacker or researcher with local access to the debugging interface would observe incorrect memory states, undermining the integrity of the debugging process.

## Affected products

- openRISC OR1200 processor commit 83ac6b42d73f00daa88a996a1f6738d5a639a105

## Timeline

- 2025-01-05: disclosed: Issue reported on GitHub
- 2025-04-26: other: Academic paper detailing SynFuzz findings published on arXiv
- 2026-07-17: advisory: CVE published to NVD

## References

- [https://github.com/openrisc/mor1kx/issues/160](https://github.com/openrisc/mor1kx/issues/160)
- [https://mason.gmu.edu/~rsaravan/projects/synfuzz/cve/cve.html](https://mason.gmu.edu/~rsaravan/projects/synfuzz/cve/cve.html)
- [https://www.arxiv.org/abs/2504.18812](https://www.arxiv.org/abs/2504.18812)

## Related threats

- [openRISC OR1200 RTL-to-netlist mismatch in program counter](https://junglewise.ai/threats/cve-2025-51679-openrisc-or1200-rtl-to-netlist-mismatch-in-program-counter)
- [openRISC OR1200 program counter update logic error](https://junglewise.ai/threats/cve-2025-51675-openrisc-or1200-program-counter-update-logic-error)