CVE-2026-88390
HighCVSS 7.7Summary
In Espruino 2v29 (commit bffc6d0), the jslGetTokenValueAsString() function has an out-of-bounds write vulnerability. Crafted JavaScript input with an overlong token can trigger a one-byte write beyond the JsLex.token buffer in RELEASE/NO_ASSERT builds, corrupting the adjacent tokenValue pointer and leading to memory corruption, application crashes, or denial of service.
Risk Assessment
An attacker could remotely execute malicious JavaScript, potentially causing application crashes or denial of service in systems using Espruino.
Recommendation
Update Espruino to a patched version or apply a workaround by limiting token length in JavaScript code.
Other vulnerabilities in Espruino
See all- CVE-2026-88389Unknown
Espruino 2v29 (commit bffc6d0) contains a NULL pointer dereference vulnerability in jslGetRawString() in src/jslex.c. Crafted raw/binary string input can cause the lexer to pass a NULL iterator target to jsvLockAgain(), leading to memory corruption and application termination or denial of service in RELEASE/NO_ASSERT builds.
- CVE-2026-88388High
Espruino 2v29 (commit bffc6d0) contains a stack-based buffer overflow vulnerability in the JavaScript error stack-trace handling path on 64-bit builds. A remote attacker can supply JavaScript input that triggers an exception and reaches jslPrintTokenLineMarker(), which passes the address of a 4-byte int column variable to jsvGetLineAndCol() as a size_t pointer. jsvGetLineAndCol() performs an 8-byte write through the mismatched pointer, overwriting adjacent stack memory.
Original NVD description (English source)
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/NO_ASSERT builds. The out-of-bounds write corrupts the adjacent tokenValue pointer, resulting in memory corruption and potentially causing application crashes or denial of service.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS