Junos OS Evolved: ACX7000 Series: Specific IPv6 transit traffic gets exceptioned to the routing-engine which causes increased CPU utilization

published 2022-10-18 4 y ago modified 2026-06-17 4 mo ago also EUVD-2022-27374

cvss: 5.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.7%; EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits: 0; none known

An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS Evolved on ACX7000 Series allows an unauthenticated network-based attacker to cause a partial Denial of Service (DoS). On receipt of specific IPv6 transit traffic, Junos OS Evolved on ACX7100-48L, ACX7100-32C and ACX7509 sends this traffic to the Routing Engine (RE) instead of forwarding it, leading to increased CPU utilization of the RE and a partial DoS. This issue only affects systems configured with IPv6. This issue does not affect ACX7024 which is supported from 22.3R1-EVO onwards where the fix has already been incorporated as indicated in the solution section. This issue affects Juniper Networks Junos OS Evolved on ACX7100-48L, ACX7100-32C, ACX7509: 21.1-EVO versions prior to 21.1R3-S2-EVO; 21.2-EVO versions prior to 21.2R3-S2-EVO; 21.3-EVO versions prior to 21.3R3-EVO; 21.4-EVO versions prior to 21.4R1-S1-EVO, 21.4R2-EVO. This issue does not affect Juniper Networks Junos OS Evolved versions prior to 21.1R1-EVO.

Patch / fix

fixed in 1

Juniper Networks Junos OS Evolved 21.1R3-S2-EVO, 21.2R3-S2-EVO, 21.3R3-EVO, 21.4R1-S1-EVO, 21.4R2-EVO

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 17 mo ago (2025-05-12)

Exploit prediction

0.68% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected products

Juniper Networks Junos OS Evolved

Classification

Weakness

CWE-754 Improper Check for Unusual or Exceptional Conditions

References

kb.juniper.net /JSA69878
vendor-advisory

Sources

CVE List CVE-2022-22227
NVD CVE-2022-22227

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Summary