No exploitation reportedFix available

CVE-2020-27299

Q: Is CVE-2020-27299 actively exploited?

Active exploitation of CVE-2020-27299 has not been confirmed. Its EPSS score was 1.7% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2020-27299?

CVE-2020-27299 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.

No exploitation reported by the sources we read.

Published2021-01-26
Fixed in6.3.0.8233
WeaknessCWE-125

Am I 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

The affected product is vulnerable to an out-of-bounds read, which may allow an attacker to obtain and disclose sensitive data information or cause the device to crash on the OPC UA Tunneller (versions prior to 6.3.0.8233).

Timeline

dates in UTC

2021-01-2619:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-27299?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-27299?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Honeywell opc ua tunneller

Branch	Affected	Fixed in	Source
6.3	< 6.3.0.8233	6.3.0.8233	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

ICSA-21-021-03 CISA1 known affected
Honeywell OPC UA Tunneller
OPC UA Tunneller: All versions prior to 6.3.0.8233

Full record on NVD

Fix

Update Honeywell opc ua tunneller to 6.3.0.8233
Vendor fix CISA ICSA-21-021-03 · 1 productHoneywell recommends upgrading Matrikon OPC UA Tunneller to Version 6.3.0.8233

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.19.1read 2026-10-23
NVDCVSS 2.06.4read 2026-10-23
CNAweakness (CWE)CWE-125read 2026-10-23
NVDweakness (CWE)CWE-125read 2026-10-23
FIRST EPSSEPSS score1.7 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Published: 2021-01-26
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2020-27299?

Is CVE-2020-27299 actively exploited?

Active exploitation of CVE-2020-27299 has not been confirmed. Its EPSS score was 1.7% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-27299?

CVE-2020-27299 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.

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Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

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