CVE-2026-56111
CVSS v3
9.1
CRITICAL
EPSS Score
0.6 %
exploit probability, as of 2026-10-19
CISA KEV
No
known exploited
Exploitation
—
SSVC status
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Affected and fixed versions
Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-56111 yet.
Description
Marlin Firmware through 2.1.2.7, fixed in commit 1f255d1, when built with MESH_BED_LEVELING enabled, contains an out-of-bounds write vulnerability in the M421 G-code handler that allows attackers to corrupt firmware memory by supplying out-of-range X and Y grid indices. Attackers can send a single crafted G-code command via USB serial, network interface, or malicious gcode file to write an attacker-controlled 32-bit float value past the z_values array bounds, corrupting adjacent firmware variables and causing denial of service or firmware state corruption.
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
- Published
- 2026-06-24
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