CVE-2021-27432
No exploitation reported by the sources we read.
- Published2021-05-20
- Fixed in1.4.365.48
- WeaknessCWE-674
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
OPC Foundation UA .NET Standard versions prior to 1.4.365.48 and OPC UA .NET Legacy are vulnerable to an uncontrolled recursion, which may allow an attacker to trigger a stack overflow.
Timeline
dates in UTC- 2021-05-2016:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-27432?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-27432?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 1.4 | < 1.4.365.48 | 1.4.365.48 | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| — | all versions | no fix published | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
ICONICS GENESIS64 and Mitsubishi Electric MC Works64 OPC UA
MobileHMI: Versions 10.97 and prior · AnalytiX: Versions 10.97 and prior · GENESIS64: Versions 10.97 and prior · +2 more
OPC Foundation UA Products Built with .NET Framework
OPC UA .NET Standard: versions prior to 1.4.365.48
Fix
- Update Opcfoundation ua .net standard stack to 1.4.365.48
- Vendor fix CISA ICSA-21-133-03 · 1 productOPC Foundation recommends users install the OPC UA .NET Standard stack update.
- Mitigation from the vendor CISA ICSA-21-294-03 · 5 productsICONICS and Mitsubishi Electric are releasing Critical Fix Rollup packages or patches that will include the solution to this vulnerability. GENESIS64 Versions 10.97.1 and later will not be vulnerable to this exploit.
- Mitigation from the vendor CISA ICSA-21-294-03 · 5 productsPlace control system networks and devices behind firewalls to isolate them from the business network.
- Mitigation from the vendor CISA ICSA-21-294-03 · 5 productsMinimize network exposure for all control system devices. Control system devices should not directly face the Internet.
- Mitigation from the vendor CISA ICSA-21-294-03 · 5 productsDo not click web links or open unsolicited attachments in e-mail messages.
- Mitigation from the vendor CISA ICSA-21-294-03 · 5 productsLeverage OPC UA security and certificates to ensure ICONICS products only connect to trusted OPC UA servers and clients.
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
- NVDCVSS 3.17.5read 2026-10-23
- NVDCVSS 2.05read 2026-10-23
- CNAweakness (CWE)CWE-674read 2026-10-23
- FIRST EPSSEPSS score2.0 %2026-10-22
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Published
- 2021-05-20
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-27432?
Is CVE-2021-27432 actively exploited?
What is the CVSS score for CVE-2021-27432?
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.