Skip to main content
CVE-2026-1301VulnerabilityPublished

CVE-2026-1301: o6 Automation Open62541 · Out-of-bounds Write

Affects o6 Automation Open62541Source CVE Database V5

0

Not known to be exploited · CVSS 6.8 Medium : upgrade to 1.5-rc2 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score
6.8Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 32% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.5-rc2
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 5 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

What to do

Upgrade o6 Automation Open62541 to 1.5-rc2.

Affected software

ProductAffectedFixed in
o6 Automation GmbHOpen62541Affected
  • >=1.5-rc1 <1.5-rc2
Fixed in
  • 1.5-rc2

AI-suggested

If you cannot patch yet, it is critical to disable PubSub and JSON encoding features if not strictly necessary or to implement strict input validation and filtering on JSON messages at network boundaries. Network segmentation should be enforced to isolate OPC UA communication channels from untrusted networks and limit exposure to potential attackers. Deploying intrusion detection systems with signatures for anomalous JSON payloads targeting OPC UA may help detect exploitation attempts. Additionally, enforcing strict authentication and authorization policies on OPC UA servers, even though this vulnerability occurs pre-authentication, can reduce overall attack surface. Regular security audits and penetration testing focused on industrial protocols should be conducted to identify and remediate similar risks.

Description

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.

References

Community reviews

Loading reviews…