An unsigned integer underflow in the PubSub signature verification path
in open62541 may allow a remote attacker to cause a denial of service
via a crafted UDP packet.

Attack Vector Network

Attack Complexity High

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
o6 Automation open62541 unaffected
Version Status Constraints
1.3.0 affected ≤ 1.3.17
1.4.0 affected ≤ 1.4.16
1.5.0 affected ≤ 1.5.4
master affected —

No data.

No data.

No data.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

o6 Automation has prepared mitigations and fixes to address these issues and recommends that users update to the newest version. The new version can be obtained by contacting o6 Automation   https://www.o6-automation.com/contact or by downloading from the following locations: https://github.com/open62541/open62541/pull/8235/commits/b666d35769ce63998442e4d0810a3fb10b50179f https://github.com/open62541/open62541/pull/8236/commits/06b99fef667c8ec5bdf0605b4f00c84fcc1d3a60 https://github.com/open62541/open62541/pull/8237/commits/1b71d9c5d9c4d02d4729b8903a52e9f530bf804e https://github.com/open62541/open62541/pull/8238/commits/afab4107bfd161da9ce8bb30ed77f3968c9c97df For more information, see open62541 Security Advisories SA-2026-0012, SA-2026-0014, and SA-2026-0015 or contact o6 Automation:  https://www.o6-automation.com/contact

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-211-08.json cve-icon
https://github.com/open62541/open62541/pull/8235/commits/b666d35769ce63998442e4d0810a3fb10b50179f cve-icon
https://github.com/open62541/open62541/pull/8236/commits/06b99fef667c8ec5bdf0605b4f00c84fcc1d3a60 cve-icon
https://github.com/open62541/open62541/pull/8237/commits/1b71d9c5d9c4d02d4729b8903a52e9f530bf804e cve-icon
https://github.com/open62541/open62541/pull/8238/commits/afab4107bfd161da9ce8bb30ed77f3968c9c97df cve-icon
https://www.cisa.gov/news-events/ics-advisories/icsa-26-211-08 cve-icon
https://www.o6-automation.com/contact cve-icon
History

Thu, 30 Jul 2026 22:30:00 +0000

Type Values Removed Values Added
Description An unsigned integer underflow in the PubSub signature verification path in open62541 may allow a remote attacker to cause a denial of service via a crafted UDP packet.
Title o6 Automation open62541 Integer Underflow
Weaknesses CWE-191
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: icscert

Published:

Updated: 2026-07-30T22:01:48.523Z

Reserved: 2026-07-27T15:02:47.793Z

Link: CVE-2026-63362

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses