VulnerabilityDeferred

CVE-2026-66364

When processing specific payload fields, an attacker controlled inner element length may exceed its enclosing length, causing the parser to over read by one byte.

HIGH 7.1EPSS 0.18%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.18%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

The GOOSE payload parser contains a boundary handling flaw that can be triggered by a single unauthenticated Layer 2 multicast frame on the process bus. When processing specific payload fields, an attacker controlled inner element length may exceed its enclosing length, causing the parser to over read by one byte. This out-of-bounds read reliably terminates the subscriber process, resulting in a denial-of-service condition.

CVSS 4.0: 7.1 HIGHCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.18% probability · 7th percentile
CISA KEV: Not listed
Weakness: CWE-125
Source: ics-cert@hq.dhs.gov

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.