CVE-2026-70388: Integer Underflow (CVSS 8.3)

Description

SOEM version 2.0.0 and earlier contains vulnerabilities where a malicious device on the network can send specially crafted messages that cause the master to write data outside allocated memory boundaries. The software performs arithmetic on message length values without proper validation, allowing negative or extremely large values to bypass safety checks. This can corrupt memory and potentially allow an attacker to execute arbitrary code on the master system.

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CVSS v3.1 Score

8.3

HIGH

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.12%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-191 CWE-191

CWE-195 CWE-195

CWE-787 Out-of-bounds Write

References

Other References

https://rt-labs.com/wp-content/uploads/2026/10/RRTL-260921-01.pdf

Frequently Asked Questions

What is CVE-2026-70388? +

SOEM version 2.0.0 and earlier contains vulnerabilities where a malicious device on the network can send specially crafted messages that cause the master to write data outside allocated memory boundaries. The software performs arithmetic on message length values without proper validation, allowing negative or extremely large values to bypass safety checks. This can corrupt memory and potentially allow an attacker to execute arbitrary code on the master system. It has a CVSS v3.1 base score of 8.3 (HIGH).

How severe is CVE-2026-70388? +

CVE-2026-70388 has a CVSS v3.1 score of 8.3 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0021, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-70388? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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