Quick answers
- Is CVE-2026-88389 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-88389 being exploited in the wild.
- How severe is CVE-2026-88389?
- Informational severity, published 25 September 2026.
- Which products and versions are affected?
- Espruino 2v29 (commit bffc6d0).
- Is there a fix for CVE-2026-88389?
- A patch was published on 2026-09-08: Fix committed at espruino/Espruino@0db0663 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-88389 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-88389?
- Check whether you run Espruino at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The jslGetRawString() function in src/jslex.c unsafely calls jsvLockAgain() on a string iterator that may be NULL if the declared length of a raw/binary string exceeds the actual input data. In debug builds, an assert catches this; in RELEASE builds compiled with -DNO_ASSERT, the NULL pointer is dereferenced for writing, causing a memory corruption or segmentation fault. The attack vector is local input to the interpreter (parsing untrusted scripts), and a fix exists that conditionally checks for NULL before calling the unsafe function.
Affected products
- Espruino Espruino 2v29 (commit bffc6d0)
Timeline
- 2026-09-25: disclosed
- 2026-09-08: patched: Fix committed at espruino/Espruino@0db0663