VDB-344585 · CVE-2026-1301 · icsa-26-036-03

o6 Automation Open62541 up to 1.5-rc1 JSON out-of-bounds write

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.
4.1	$0-$5k	0.00

Summaryinfo

A vulnerability has been found in o6 Automation Open62541 up to 1.5-rc1 and classified as critical. Affected is an unknown function of the component JSON Handler. The manipulation leads to out-of-bounds write. This vulnerability is referenced as CVE-2026-1301. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, has been found in o6 Automation Open62541 up to 1.5-rc1. This issue affects an unknown part of the component JSON Handler. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is availability. The summary by CVE is:

In builds with PubSub and JSON enabled, a crafted JSON message can cause the decoder to write beyond a heap-allocated array before authentication, reliably crashing the process and corrupting memory.

The weakness was published by Andrew Fasano as icsa-26-036-03. The advisory is shared at cisa.gov. The identification of this vulnerability is CVE-2026-1301 since 01/21/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available.

Upgrading to version 1.5-rc2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-5530). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Automation Software

Vendor

o6 Automation

Name

Open62541

Version

1.5-rc1

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.1

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
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Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Open62541 1.5-rc2

Timelineinfo

01/21/2026 CVE reserved
02/05/2026 +15 days Advisory disclosed
02/05/2026 +0 days VulDB entry created
02/06/2026 +1 days VulDB entry last update

Sourcesinfo

Advisory: icsa-26-036-03
Researcher: Andrew Fasano
Status: Confirmed

CVE: CVE-2026-1301 (🔒)
GCVE (CVE): GCVE-0-2026-1301
GCVE (VulDB): GCVE-100-344585
EUVD: 🔒

Entryinfo

Created: 02/05/2026 20:20
Updated: 02/06/2026 14:52
Changes: 02/05/2026 20:20 (70), 02/06/2026 14:52 (1)
Complete: 🔍
Cache ID: 216::103

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