CVE-2020-9307

HSR ring disruption via forged packet processing

Published Feb 11, 2021 · Updated Aug 4, 2024

Denial of service in Hirschmann OS2, RSP, and RSPE devices before HiOS 08.3.00 allows attackers to disrupt an HSR ring. An HSR ring port enters an infinite loop when it processes a specifically forged packet received on one of the two redundant links. The attacker must have adjacent access to an HSR redundant link; one attacked device removes redundancy, while attacks against two devices partition the ring and interrupt cross-partition communication.

CVSS severity6.5
Medium
EPSS probability0.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Hirschmann OS2, RSP, and RSPE devices before HiOS 08.3.00 allows attackers to disrupt an HSR ring. An HSR ring port enters an infinite loop when it processes a specifically forged packet received on one of the two redundant links. The attacker must have adjacent access to an HSR redundant link; one attacked device removes redundancy, while attacks against two devices partition the ring and interrupt cross-partition communication.

The record

CVE
CVE-2020-9307
Published
Feb 11, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-835, T1498
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1NIST NVDAV:A/AC:L/Au:N/C:N/I:N/A:C
6.5NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1498Network Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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