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Fencer Vulns
high 7.5

CVE-2024-39547 json

Junos OS and Junos OS Evolved: cRPD: Receipt of crafted TCP traffic can trigger high CPU utilization

published 2024-10-11 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-38073

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

An Improper Handling of Exceptional Conditions vulnerability in the rpd-server of Juniper Networks Junos OS and Junos OS Evolved within cRPD allows an unauthenticated network-based attacker sending crafted TCP traffic to the routing engine (RE) to cause a CPU-based Denial of Service (DoS).

If specially crafted TCP traffic is received by the control plane, or a TCP session terminates unexpectedly, it will cause increased control plane CPU utilization by the rpd-server process.

While not explicitly required, the impact is more severe when RIB sharding is enabled.

Task accounting shows unexpected reads by the RPD Server jobs for shards:

user@junos> show task accounting detail ... read:RPD Server.0.0.0.0+780.192.168.0.78+48886 TOT:00000003.00379787 MAX:00000000.00080516 RUNS: 233888\ read:RPD Server.0.0.0.0+780.192.168.0.78+49144 TOT:00000004.00007565 MAX:00000000.00080360 RUNS: 233888\ read:RPD Server.0.0.0.0+780.192.168.0.78+49694 TOT:00000003.00600584 MAX:00000000.00080463 RUNS: 233888\ read:RPD Server.0.0.0.0+780.192.168.0.78+50246 TOT:00000004.00346998 MAX:00000000.00080338 RUNS: 233888\

This issue affects:

Junos OS with cRPD:

* All versions before 21.2R3-S8,  * 21.4 before 21.4R3-S7,  * 22.1 before 22.1R3-S6,  * 22.2 before 22.2R3-S4,  * 22.3 before 22.3R3-S3,  * 22.4 before 22.4R3-S2,  * 23.2 before 23.2R2-S2,  * 24.2 before 24.2R2;

Junos OS Evolved with cRPD:

* All versions before 21.4R3-S7-EVO,  * 22.2 before 22.2R3-S4-EVO,  * 22.3 before 22.3R3-S3-EVO,  * 22.4 before 22.4R3-S2-EVO,  * 23.2 before 23.2R2-EVO.

Patch / fix

  • Juniper Networks Junos OS 21.2R3-S8, 21.4R3-S7, 22.1R3-S6, 22.2R3-S4, 22.3R3-S3, 22.4R3-S2, 23.2R2-S2, 24.2R2
  • Juniper Networks Junos OS Evolved 21.4R3-S7-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO, 22.4R3-S2-EVO, 23.2R2-EVO
  • juniper junos 21.2r3-s8, 21.4r3-s7, 22.1r3-s6, 22.2r3-s4, 22.3r3-s3, 22.4r3-s2, 23.2r2-s2, 24.2r2
  • juniper junos_evolved 21.4r3-s7-evo, 22.2r3-s4-evo, 22.3r3-s3-evo, 22.4r3-s2-evo, 23.2r2-evo

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.97% chance of exploitation in the next 30 days, higher than 61% 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
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:U
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:X/RE:X/U:X

Affected products

  • Juniper Networks Junos OS
  • Juniper Networks Junos OS Evolved
  • juniper junos
  • juniper junos_evolved

Classification

Weakness
  • CWE-755 Improper Handling of Exceptional Conditions

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.