OCaml up to 4.14.2/5.4.0 Marshal runtime/intern.c readblock buffer over-read

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.9$0-$5k0.00

Summaryinfo

A vulnerability was found in OCaml up to 4.14.2/5.4.0. It has been classified as problematic. Affected by this vulnerability is the function readblock of the file runtime/intern.c of the component Marshal Handler. This manipulation causes buffer over-read. This vulnerability appears as CVE-2026-28364. The attack requires local access. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in OCaml up to 4.14.2/5.4.0. It has been declared as problematic. Affected by this vulnerability is the function readblock of the file runtime/intern.c of the component Marshal Handler. The manipulation with an unknown input leads to a buffer over-read vulnerability. The CWE definition for the vulnerability is CWE-126. The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In OCaml before 4.14.3 and 5.x before 5.4.1, a buffer over-read in Marshal deserialization (runtime/intern.c) enables remote code execution through a multi-phase attack chain. The vulnerability stems from missing bounds validation in the readblock() function, which performs unbounded memcpy() operations using attacker-controlled lengths from crafted Marshal data.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-28364 since 02/27/2026. The exploitation appears to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 300178 (Linux Distros Unpatched Vulnerability : CVE-2026-28364), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.14.3 or 5.4.1 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (300178). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.0
VulDB Meta Temp Score: 6.9

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔒

CNA Base Score: 7.9
CNA Vector (MITRE): 🔒

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer over-read
CWE: CWE-126 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 300178
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-28364

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: OCaml 4.14.3/5.4.1

Timelineinfo

02/27/2026 Advisory disclosed
02/27/2026 +0 days CVE reserved
02/27/2026 +0 days VulDB entry created
03/06/2026 +7 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-28364 (🔒)
GCVE (CVE): GCVE-0-2026-28364
GCVE (VulDB): GCVE-100-348073

Entryinfo

Created: 02/27/2026 07:25
Updated: 03/06/2026 22:45
Changes: 02/27/2026 07:25 (64), 03/02/2026 18:22 (2), 03/06/2026 22:45 (12)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to stay up to date on a daily basis?

Enable the mail alert feature now!