---
id: CVE-2026-88355
title: >-
  An incorrect buffer size calculation vulnerability exists in tinyexpr commit
  4a7456e in new_expr()
summary: >-
  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…
severity: none
published: '2026-09-24'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T21:08:55.030'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-88355'
references:
  - url: 'https://github.com/codeplea/tinyexpr/issues/145'
    label: cve@mitre.org
  - url: >-
      https://github.com/szaydel/tinyexpr/commit/fe7459728c2ab8d2f91365abe56601cdd0e24f9b
    label: cve@mitre.org
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-24T15:45:56.663Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.