CVE-2026-88355

High severity, CVSS 7.5. EPSS: 0.3% chance of exploitation in the next 30 days.

An incorrect buffer size calculation vulnerability exists in tinyexpr commit 4a7456e in new_expr(). For arity-0 expression nodes, including constants, variables, and zero-argument functions, the function allocates less memory than sizeof(te_expr) but treats the returned allocation as a complete te_expr object. This results in undefined behavior and can cause deterministic process termination in UBSan-instrumented builds.

Published 2026-09-24. Last modified 2026-10-06.