libIEC61850: Remote NULL dereference in MMS Read alternate-access sub-array path leads to server-side DoS

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

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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, alternateArrayAccess in src/mms/iso_mms/server/mms_read_service.c does not validate an alternate-access sub-array range when numberOfElements is greater than zero. An out-of-range MmsValue_getElement call returns NULL, and the sub-array branch passes that value to MmsValue_isDeletable, causing a NULL pointer dereference. A remote MMS Read request can therefore crash servers whose data models contain arrays, while the single-element error path handles the same invalid index safely. This issue is fixed in version 1.6.2.

Source published

16 Oct 2026 15:45:32 UTC

Source modified

21 Oct 2026 02:22:38 UTC

Observed here

23 Oct 2026 15:48:27 UTC

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CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H