Vulnerability · Published Sep 24, 2026 · Assigned by mitre
CVE-2026-88355
High 7.5
In plain English
A high-severity security flaw in the affected software. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
Weakness: CWE-131 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H