Vulnerability/
https://seclists.org/oss-sec/2026/q1/231

https://seclists.org/oss-sec/2026/q1/231: OSEC-2026-01 in the OCaml runtime: Buffer Over-ad in OCaml Marshal Deserialization

Q: Which OCaml releases need remediation?

OCaml versions earlier than 4.14.3 are affected. In the 5.x series, versions from 5.0 up to, but not including, 5.4.1 are affected.

Q: What level of attacker access does the severity assessment assume?

The CVSS vector rates the attack as local, with low attack complexity and no privileges or user interaction required. It rates confidentiality impact as high, integrity impact as low, and availability impact as none.

Q: How can I determine whether an installation is in scope?

Check the OCaml runtime version in use. Installations below 4.14.3, or running a 5.x version below 5.4.1, are affected.

Published Feb 27, 2026

Updated

Affected Software

1 affected component

ocaml<4.14.3, >=5<5.4.1

Frequently Asked Questions

Which OCaml releases need remediation?

OCaml versions earlier than 4.14.3 are affected. In the 5.x series, versions from 5.0 up to, but not including, 5.4.1 are affected.

What level of attacker access does the severity assessment assume?

The CVSS vector rates the attack as local, with low attack complexity and no privileges or user interaction required. It rates confidentiality impact as high, integrity impact as low, and availability impact as none.

How can I determine whether an installation is in scope?

Check the OCaml runtime version in use. Installations below 4.14.3, or running a 5.x version below 5.4.1, are affected.

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