CVE-2026-88355

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.

Overview

State: PUBLISHED
Assigner (CNA): mitre
CVSS severity: —
CVSS score: —
CVSS vector: —
Effective score: no score available from CNA, NVD, or AI yet
CWE(s): —
Reserved: 2026-09-10
Published: 2026-09-24 00:00 UTC
Last updated: 2026-09-24 15:27 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/88xxx/CVE-2026-88355.json

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European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-86286
Assigner: mitre
Published: Sep 24, 2026, 12:00:00 AM
Updated: Sep 24, 2026, 3:27:36 PM
EUVD base score: 0.0 / 10
EUVD-reported EPSS: 0.0000
Vendors: n/a
Products: n/a (n/a)
Aliases: GHSA-8v6x-g49v-x5cf

ENISA 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.

EUVD references (2)

Affected products (1)

Vendor	Product	Versions	Platforms
n/a	n/a	`n/a` (affected)	—

Vendor references (2)

References embedded in the original CVE record by the assigning CNA.

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

Remediations (10)

Security Update Guide - Microsoft

web:msrc.microsoft.com

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

2026-09-25 10:46 UTC
Security Update Guide - Microsoft Security Response Center

web:msrc.microsoft.com

Security Update Guide - Microsoft Security Response Center

2026-09-25 10:46 UTC
Cisco Advance Notification for Publication of September 16, 2026 ...

web:sec.cloudapps.cisco.com

On September 16, 2026 , the Cisco Product Security Incident Response Team (PSIRT) published the advisories that are listed in the following tables. To remediate these vulnerabilities, Cisco strongly recommends that customers upgrade to the fixed software that is indicated in the advisories. For more information about changes in Cisco PSIRT vulnerability disclosure, see Strengthening the ...

2026-09-25 10:46 UTC
Microsoft Patch Tracker (September 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-09-25 10:46 UTC
What Is CVE Remediation in 2026? - aikido.dev

web:www.aikido.dev

CVE remediation is fixing known flaws in the software you run. Why upgrading often fails, what remediation actually involves, and how backporting fixes it.

2026-09-25 10:46 UTC
Microsoft August 2026 Patch Tuesday fixes 400 flaws, 3 zero-days

web:www.bleepingcomputer.com

Today is Microsoft's August 2026 Patch Tuesday, and with it comes security updates for a massive 400 flaws, including one actively exploited and two publicly disclosed zero-day vulnerabilities.

2026-09-25 10:46 UTC
CVE: Common Vulnerabilities and Exposures

web:www.cve.org

At cve .org, we provide the authoritative reference method for publicly known information-security vulnerabilities and exposures

2026-09-25 10:46 UTC
Oracle Critical Patch Update Advisory - July 2026

web:www.oracle.com

This Critical Patch Update contains 1448 new security patches across the product families listed below. Please note that a My Oracle Support (MOS) note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at July 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-25 10:46 UTC
Patch Tuesday - August 2026 - Rapid7

web:www.rapid7.com

Microsoft is publishing 421 vulnerabilities on August 2026 Patch Tuesday, including 236 vulnerabilities in Windows. Rapid7 has disclosed the second in a two-part critical remote execution vulnerability chain in SharePoint.

2026-09-25 10:46 UTC
Patch Tuesday September 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's September 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-09-25 10:46 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-88355.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-24T15:27:36.765Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://github.com/codeplea/tinyexpr/issues/145"
        },
        {
          "url": "https://github.com/szaydel/tinyexpr/commit/fe7459728c2ab8d2f91365abe56601cdd0e24f9b"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-88355",
    "datePublished": "2026-09-24T00:00:00.000Z",
    "dateReserved": "2026-09-10T00:00:00.000Z",
    "dateUpdated": "2026-09-24T15:27:36.765Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}