CVE-2026-88390: High severity Espruino Espruino vulnerability
An out-of-bounds write vulnerability in jslGetTokenValueAsString() in Espruino 2v29 (commit bffc6d0) allows crafted JavaScript input containing an overlong token to trigger a one-byte write beyond the JsLex.token buffer in RELEASE/NOASSERT builds. The out-of-bounds write corrupts the adjacent tokenValue pointer, resulting in memory corruption and potentially causing application crashes or denial of service.
Affected Software
Event History
Frequently Asked Questions
Which builds are affected?
The issue is described in Espruino 2v29 at commit bffc6d0, specifically in RELEASE/NO_ASSERT builds. The provided data does not establish whether other versions or build configurations are affected.
What does an attacker need to do to trigger the flaw?
An attacker needs to cause the affected Espruino instance to process crafted JavaScript containing an overlong token. The malformed token triggers a one-byte write beyond the JsLex.token buffer.
What is the likely impact of successful exploitation?
The out-of-bounds write can corrupt the adjacent tokenValue pointer, causing memory corruption. The stated potential outcome is an application crash or denial of service.