Espruino JavaScript Error Stack-Trace jsvGetLineAndCol stack-based overflow

Summaryinfo

A vulnerability was found in Espruino. It has been declared as critical. The affected element is the function jsvGetLineAndCol of the component JavaScript Error Stack-Trace Handler. The manipulation results in stack-based overflow. This vulnerability is known as CVE-2026-88388. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability, which was classified as critical, was found in Espruino (version now known). Affected is the function jsvGetLineAndCol of the component JavaScript Error Stack-Trace Handler. The manipulation with an unknown input leads to a stack-based overflow vulnerability. CWE is classifying the issue as CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-88388 since 09/10/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/24/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Name

• Espruino

Website

• Product: https://github.com/espruino/Espruino/

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