CVE-2026-88390 Espruino - Out of Bounds Write

Espruino 2v29 contains a buffer overflow caused by an out-of-bounds write in jslGetTokenValueAsString() when processing overlong JavaScript tokens, letting attackers cause memory corruption and denial of service, exploit requires crafted JavaScript input.

CVSS base score 7.7 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.17% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Out of Bounds Write
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Published
24 September 2026
Updated
15 October 2026
Weakness
CWE-787

Vendor fix

Update to the latest version of Espruino.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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