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Fencer Vulns
medium 6.5

CVE-2020-9307 json

Hirschmann OS2, RSP, and RSPE devices before HiOS 08.3.00 allow a denial of service.

published 2021-02-11 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-30131

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

Hirschmann OS2, RSP, and RSPE devices before HiOS 08.3.00 allow a denial of service. An unauthenticated, adjacent attacker can cause an infinite loop on one of the HSR ring ports of the device. This effectively breaks the redundancy of the HSR ring. If the attacker can perform the same attack on a second device, the ring is broken into two parts (thus disrupting communication between devices in the different parts).

Patch / fix

  • belden hirschmann_hios 07.1.00, 08.3.00

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-075-03 updated cvss 6.5

Hitachi ABB Power Grids AFS Series

  • Hitachi Energy AFS660-SR 7.0.07 Hitachi Energy AFS665-SR 7.0.07
    affected: mitigation “For additional information and support, contact a product provider or Hitachi ABB Power Grids service organization. For contact information, see Hitachi ABB Power Grids contact-centers.” search.abb.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Exploit prediction

0.59% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 6.1 AV:A/AC:L/Au:N/C:N/I:N/A:C

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.