CVE-2026-65200: Integer Underflow (CVSS 3.5)

Description

The openUBMC device-management process parses PLDM-over-MCTP and NCSI-over-MCTP responses from on-bus devices, and three response parsers in the shared transport libraries subtract a fixed header or reserved-field size from a device-supplied response length without a lower-bound check. An undersized response wraps the unsigned length difference to a very large value, and the parser then reads far past the response buffer. The affected code sits in the base (non-vendor) PLDM control class and the Huawei NCSI driver, so it is reachable for any PLDM endpoint or Huawei NIC on the internal management bus, unlike the vendor-specific wangxun parser tracked separately.

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CVSS v3.1 Score

3.5

LOW

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

EPSS — Exploit Prediction

0.0014

Probability of exploitation

0.03%

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

References

Other References

https://www.runzero.com/advisories/huawei-malicious-device-integer-underflow-cve-2026-65200

Frequently Asked Questions

What is CVE-2026-65200? +

The openUBMC device-management process parses PLDM-over-MCTP and NCSI-over-MCTP responses from on-bus devices, and three response parsers in the shared transport libraries subtract a fixed header or reserved-field size from a device-supplied response length without a lower-bound check. An undersized response wraps the unsigned length difference to a very large value, and the parser then reads far past the response buffer. The affected code sits in the base (non-vendor) PLDM control class and the Huawei NCSI driver, so it is reachable for any PLDM endpoint or Huawei NIC on the internal management bus, unlike the vendor-specific wangxun parser tracked separately. It has a CVSS v3.1 base score of 3.5 (LOW).

How severe is CVE-2026-65200? +

CVE-2026-65200 has a CVSS v3.1 score of 3.5 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0014, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-65200? +

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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