CVE-2023-28961Network attack vector

IPv6 filtering bypass via rejected AH rule

Published Apr 17, 2023 · Updated Feb 6, 2025

Improper data-type handling in Junos OS on ACX Series devices allows remote attackers to bypass configured IPv6 filtering. When a filter term matches from next-header ah, PFE rule preparation rejects IP protocol 51 and fails to install the filter while the CLI commit gives no immediate warning. Exploitation requires an affected ACX device with that filter term; valid packets intended to be dropped can then pass to or through the device.

CVSS severity5.8
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper data-type handling in Junos OS on ACX Series devices allows remote attackers to bypass configured IPv6 filtering. When a filter term matches from next-header ah, PFE rule preparation rejects IP protocol 51 and fails to install the filter while the CLI commit gives no immediate warning. Exploitation requires an affected ACX device with that filter term; valid packets intended to be dropped can then pass to or through the device.

The record

CVE
CVE-2023-28961
Published
Apr 17, 2023
Updated
Feb 6, 2025
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-241, T1562.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 6, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=20.4 <20.4R3-S4
  2. Affected versionversion=21.1 <21.1R3-S3
  3. Affected versionversion=21.2 <21.2R3-S4
  4. Affected versionversion=21.3 <21.3R3
  5. Affected versionversion=21.4 <21.4R3
  6. Affected versionversion=22.1 <22.1R2
  7. Affected versionversion=unspecified <20.2R3-S7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=20.4 <20.4R3-S4; version=21.1 <21.1R3-S3; version=21.2 <21.2R3-S4; version=21.3 <21.3R3; version=21.4 <21.4R3; version=22.1 <22.1R2; version=unspecified <20.2R3-S7

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
5.8Juniper NetworksCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-241Improper Handling of Unexpected Data Type
T1562.004Impair Defenses: Disable or Modify System Firewall

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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