---
title: "CVE-2026-89087: OCaml cstruct - Out of Bounds Read"
description: "OCaml cstruct before 6.3.0 contains an out of bounds read caused by mishandling indexes, letting attackers potentially cause denial of service or information disclosure, exploit requires crafted input."
url: https://panop.io/threat-heartbeat/CVE-2026-89087/
---

# CVE-2026-89087 OCaml cstruct - Out of Bounds Read

OCaml cstruct before 6.3.0 contains an out of bounds read caused by mishandling indexes, letting attackers potentially cause denial of service or information disclosure, exploit requires crafted input.

CVSS base score 7.3 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.32% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89087)

## Details

Type

Out of Bounds Read

Impact

Denial Of Service, Information Disclosure

CVSS vector

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

Published

10 September 2026

Updated

15 October 2026

Weakness

[CWE-573](https://cwe.mitre.org/data/definitions/573.html)

## Vendor fix

Upgrade to version 6.3.0 or later.

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-2026-89087](https://nvd.nist.gov/vuln/detail/CVE-2026-89087)
- [https://osv.dev/vulnerability/OSEC-2026-20](https://osv.dev/vulnerability/OSEC-2026-20)

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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

Panop answers these inside your environment, for this CVE and every other finding.

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