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Fencer Vulns
high 7.5

CVE-2024-21604 json

Junos OS Evolved: A high rate of specific traffic will cause a complete system outage

published 2024-01-12 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-19252

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

An Allocation of Resources Without Limits or Throttling vulnerability in the kernel of Juniper Networks Junos OS Evolved allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS).

If a high rate of specific valid packets are processed by the routing engine (RE) this will lead to a loss of connectivity of the RE with other components of the chassis and thereby a complete and persistent system outage. Please note that a carefully designed lo0 firewall filter will block or limit these packets which should prevent this issue from occurring.

The following log messages can be seen when this issue occurs:

<host> kernel: nf_conntrack: nf_conntrack: table full, dropping packet This issue affects Juniper Networks Junos OS Evolved:

* All versions earlier than 20.4R3-S7-EVO; * 21.2R1-EVO and later versions; * 21.4-EVO versions earlier than 21.4R3-S5-EVO; * 22.1-EVO versions earlier than 22.1R3-S2-EVO; * 22.2-EVO versions earlier than 22.2R3-EVO; * 22.3-EVO versions earlier than 22.3R2-EVO; * 22.4-EVO versions earlier than 22.4R2-EVO.

Patch / fix

  • Juniper Networks Junos OS Evolved 20.4R3-S7-EVO, 21.4R3-S5-EVO, 22.1R3-S2-EVO, 22.2R3-EVO, 22.3R2-EVO, 22.4R2-EVO

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
18 mo ago

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Juniper Networks Junos OS Evolved

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

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.