CVE-2026-48503
HIGHDescription
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.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 39% of all known CVEs.
References
Related Vulnerabilities
Other CWE-191 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2014-0497 | Critical | 9.8 | 100% | KEV | Fix |
| CVE-2020-36228 | High | 7.5 | 85% | - | Fix |
| CVE-2020-36221 | High | 7.5 | 85% | - | Fix |
| CVE-2024-38063 | Critical | 9.8 | 71% | - | Fix |
| CVE-2017-14496 | High | 7.5 | 69% | - | Fix |
| CVE-2004-0184 | Medium | 5.0 | 60% | - | Fix |
Common questions
How do I fix CVE-2026-48503?
No published fix for CVE-2026-48503 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-48503 being actively exploited?
Not that we know of. CVE-2026-48503 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.46% is the estimated probability that it will be exploited in the next 30 days. That is higher than 39% of all scored CVEs.
How severe is CVE-2026-48503?
CVE-2026-48503 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-16.