Vulnerability · CVE-2026-1301
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
Published Feb 5, 2026 · catalog updated Feb 5, 2026 · o6 Automation GmbH Open62541
Last checked Nov 7, 2026. A connected source was read within the last 7 days.
Check if you run it
No confirmed exploitation is on record for CVE-2026-1301. EPSS is 0.38%. Act only if a listed version of o6 Automation GmbH Open62541 is installed.
Gaps on this record
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- Medium6.8
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.38%
- Remediation
- Version ranges on file
- Affected products
- vendor o6 Automation GmbH Open62541 1.5-rc1 <1.5-rc2
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.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- vendor o6 Automation GmbH Open62541 1.5-rc1 <1.5-rc21.5-rc1 <1.5-rc2
How to fix CVE-2026-1301
Upgrade
CVE-2026-1301 lists a fix boundary at 1.5-rc2. Compare the installed build with that boundary before you change production.
Version check
Seen in 1.5-rc1 <1.5-rc2
Advisory
Open the cve_org record and follow its fix.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-1301. EPSS is 0.38%. Act only if a listed version of o6 Automation GmbH Open62541 is installed.
Which versions are affected?
Compare what you have installed with o6 Automation GmbH Open62541 1.5-rc1 <1.5-rc2 1.5-rc1 <1.5-rc2. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
No weakness class is stored. EPSS 0.38%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Feb 5, 2026 · EUVD
Detected
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.
Feb 5, 2026 · EUVD
Updated
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.
Sources
- CVE.orgVulnerability recordCVE-2026-1301
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-1301
30-day exploitation probability 0.38%
first.org - EUVDVulnerability recordEUVD-2026-5530
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.
euvd.enisa.europa.eu
References
Freshness
Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.
- FIRST EPSSNov 7, 2026
- CVE.orgNov 4, 2026
- EUVDNov 3, 2026