Integer underflow in libIEC61850 - CVE-2026-48503
Published: June 18, 2026
Vulnerability identifier: #VU134848
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-48503
CWE-ID: CWE-191
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: MZ Automation
Affected software:
libIEC61850
libIEC61850
Detailed vulnerability description
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to integer underflow in the MMS file service when processing a fileOpen request with an out-of-range initialPosition followed by fileRead. A remote attacker can send crafted MMS file service requests to disclose sensitive information.
The disclosed data can include stale bytes from a previous fileRead response on the same connection, protocol fragments, and residual data left in the connection send buffer.
How to mitigate CVE-2026-48503
Install security update from vendor's website.