CVE-2026-63362

o6 Automation open62541 Integer Underflow

8.2 High

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 profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

1.82%Up 0.3 points since Jul 31, 2026

What each source reports

CVE List Score used 8.2

o6 Automation open62541 Integer Underflow

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.

Record: CVE-2026-63362
CVSS 4.0: 8.2 HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-191
Updated: 2026-11-02

EUVDEUVD-2026-51336 8.2

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.

Record: EUVD-2026-51336
CVSS 4.0: 8.2 HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-qv76-j3j3-2f94 8.2

An unsigned integer underflow in the PubSub signature verification path in open62541 may allow a...

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.

Record: GHSA-qv76-j3j3-2f94
CVSS 4.0: 8.2 HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-191
Updated: 2026-11-02

NVD 8.2

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.

Record: CVE-2026-63362
CVSS 4.0: 8.2 HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-191
Updated: 2026-11-02

OSV 8.2

o6 Automation open62541 Integer Underflow

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.

Record: CVE-2026-63362
CVSS 4.0: 8.2 HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness: CWE-191
Updated: 2026-11-02

OSVDEBIAN-CVE-2026-63362 8.2

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.

Record: DEBIAN-CVE-2026-63362
CVSS 4.0: 8.2 HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-63362 8.2

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.

Record: UBUNTU-CVE-2026-63362
CVSS 4.0: 8.2 HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`open62541` Debian:13	All versions, plus listed versions 1.4.11.1-11.4.18-1	None known
`open62541` Debian:14	All versions, plus listed versions 1.4.11.1-11.4.18-1	None known
`open62541` Ubuntu:26.10	All versions, plus listed versions 1.4.11.1-1build11.4.18-1	None known
`open62541` Ubuntu:26.04:LTS	All versions, plus listed versions 1.4.11.1-11.4.11.1-1build1	None known

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-63362 is a high vulnerability (CVSS 8.2) in O6 Automation Open62541, published July 30, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.82%, the 78th percentile. No source names a fixed version.

References

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