---
title: "CVE-2026-88355: tinyexpr - Buffer Overflow"
description: "tinyexpr contains a buffer overflow caused by incorrect buffer size calculation in new_expr() for arity-0 expression nodes, letting attackers cause undefined behavior and process termination, exploit requires crafted input."
url: https://panop.io/threat-heartbeat/CVE-2026-88355/
---

# CVE-2026-88355 tinyexpr - Buffer Overflow

tinyexpr contains a buffer overflow caused by incorrect buffer size calculation in new\_expr() for arity-0 expression nodes, letting attackers cause undefined behavior and process termination, exploit requires crafted input.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.34% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-88355)

## Details

Type

Buffer Overflow

Impact

Denial Of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Published

24 September 2026

Updated

15 October 2026

Weakness

[CWE-131](https://cwe.mitre.org/data/definitions/131.html)

## Vendor fix

Update to the latest version containing the fix.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-88355](https://nvd.nist.gov/vuln/detail/CVE-2026-88355)
- [https://github.com/szaydel/tinyexpr/commit/fe7459728c2ab8d2f91365abe56601cdd0e24f9b](https://github.com/szaydel/tinyexpr/commit/fe7459728c2ab8d2f91365abe56601cdd0e24f9b)
- [https://github.com/codeplea/tinyexpr/issues/145](https://github.com/codeplea/tinyexpr/issues/145)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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