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No exploitation reported

CVE-2020-6994

No exploitation reported by the sources we read.

  • Published2020-04-03
  • WeaknessCWE-12 · CWE-120

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

A buffer overflow vulnerability was found in some devices of Hirschmann Automation and Control HiOS and HiSecOS. The vulnerability is due to improper parsing of URL arguments. An attacker could exploit this vulnerability by specially crafting HTTP requests to overflow an internal buffer. The following devices using HiOS Version 07.0.02 and lower are affected: RSP, RSPE, RSPS, RSPL, MSP, EES, EES, EESX, GRS, OS, RED. The following devices using HiSecOS Version 03.2.00 and lower are affected: EAGLE20/30.

Timeline

dates in UTC
  1. 2020-04-0319:15CVE 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-2020-6994?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-6994?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Belden hirschmann hiosversion to verify
BranchAffectedFixed in
7.0≤ 07.0.02no fix published
Belden hirschmann hisecosversion to verify
BranchAffectedFixed in
3.2≤ 03.2.00no fix published

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-22-270-01 CISA1 known affected

    Hitachi Energy AFS660/AFS665

    AFS660/AFS665: Releases 7.0.02 or prior

  • ICSA-22-263-02 CISA2 known affected

    Hitachi Energy AFF660/665 Series

    Hitachi Energy AFF660 FW: Versions 03.0.02 and prior · Hitachi Energy AFF665 FW: Versions 03.0.02 and prior

  • ICSA-20-091-01 CISA2 known affected

    Hirschmann Automation and Control HiOS and HiSecOS Products

    EAGLE20/30: HiSecOS Version 03.2.00 · RSP RSPE RSPS RSPL MSP EES EES EESX GRS OS RED: HiOS Version 07.0.02 and lower

Full record on NVD

Fix

  1. Mitigation from the vendor CISA ICSA-22-270-01 · 1 productHitachi Energy recommends users update to 7.1.05 or later or apply mitigation strategies.
  2. Mitigation from the vendor CISA ICSA-22-270-01 · 1 productPhysically protect process control systems from unauthorized direct access.
  3. Mitigation from the vendor CISA ICSA-22-270-01 · 1 productSeparate process control systems from the internet and other networks using a firewall system with minimal open ports.
  4. Mitigation from the vendor CISA ICSA-22-270-01 · 1 productProcess control systems should not be used for internet surfing, instant messaging, or email.
  5. Mitigation from the vendor CISA ICSA-22-270-01 · 1 productPortable computers and removable storage media should be carefully scanned for viruses before connecting to a control system.
  6. Mitigation from the vendor CISA ICSA-22-270-01 · 1 productFor more information, see Hitachi Energy advisory 8DBD000122.

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVSS 3.19.8read 2026-10-23
  • NVDCVSS 2.07.5read 2026-10-23
  • CNAweakness (CWE)CWE-12read 2026-10-23
  • NVDweakness (CWE)CWE-120read 2026-10-23
  • FIRST EPSSEPSS score1.6 %2026-10-22

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2020-04-03
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-6994?

A buffer overflow vulnerability was found in some devices of Hirschmann Automation and Control HiOS and HiSecOS. The vulnerability is due to improper parsing of URL arguments. An attacker could exploit this vulnerability by specially crafting HTTP requests to overflow an internal buffer. The following devices using HiOS Version 07.0.02 and lower are affected: RSP, RSPE, RSPS, RSPL, MSP, EES, EES, EESX, GRS, OS, RED. The following devices using HiSecOS Version 03.2.00 and lower are affected: EAGLE20/30.

Is CVE-2020-6994 actively exploited?

Active exploitation of CVE-2020-6994 has not been confirmed. Its EPSS score was 1.6% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-6994?

CVE-2020-6994 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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