CVE-2021-27434
Products with Unified Automation .NET based OPC UA Client/Server SDK Bundle: Versions V3.0.7 and prior (.NET 4.5, 4.0, and 3.5 Framework versions only) are vulnerable to an uncontrolled recursion, which may allow an attacker to trigger a stack overflow.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.74%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Products with Unified Automation .NET based OPC UA Client/Server SDK Bundle: Versions V3.0.7 and prior (.NET 4.5, 4.0, and 3.5 Framework versions only) are vulnerable to an uncontrolled recursion, which may allow an attacker to trigger a stack overflow.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 1.74% probability · 78th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-200, CWE-674
- Affected
- unified-automation/.net based opc ua client\/server sdk
- Source
- ics-cert@hq.dhs.gov
EPSS 1.7% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://us-cert.cisa.gov/ics/advisories/icsa-21-133-04Third Party Advisory, US Government Resource
- https://us-cert.cisa.gov/ics/advisories/icsa-21-133-04Third Party Advisory, US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.