Integer overflow in Mz-Automation Libiec61850
CVE-2026-48503
libIEC61850 is an open-source implementation of IEC 61850 client and server protocols including MMS, GOOSE, Sampled Values, and R-Session. Prior to 1.6.2, the MMS file service in src/mms/iso_mms/server/mms_file_service.c accepts an out-of-range initialPosition in fileOpen and stores it in the file-read state. The fileRead path then subtracts the larger read position from the file size using unsigned arithmetic and fails to limit the response to the actual FileSystem_readFile return value. The oversized response can include stale bytes from the reused connection buffer after the requested file contents, disclosing prior response data and protocol fragments to an unauthenticated remote client when the file service is enabled. This issue is fixed in version 1.6.2.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Mz-Automation Libiec61850 — versions < 1.6.2
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-48503?
- CVE-2026-48503 is a high-severity vulnerability in Mz-Automation Libiec61850, classified under Integer Underflow. CVSS score: 7.5/10. Published 2026-10-16.
- How severe is CVE-2026-48503?
- High severity. CVSS v3 base score is 7.5 out of 10.