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Fencer Vulns
medium 6.5

CVE-2024-21618 json

Junos OS and Junos OS Evolved: When LLDP is enabled and a malformed LLDP packet is received, l2cpd crashes

published 2024-04-12 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-19266

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 22%
public exploits
0
none known

Summary

An Access of Memory Location After End of Buffer vulnerability in the Layer-2 Control Protocols Daemon (l2cpd) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause Denial of Service (DoS).

On all Junos OS and Junos OS Evolved platforms, when LLDP is enabled on a specific interface, and a malformed LLDP packet is received, l2cpd crashes and restarts. The impact of the l2cpd crash is reinitialization of STP protocols (RSTP, MSTP or VSTP), and MVRP and ERP. Also, if any services depend on LLDP state (like PoE or VoIP device recognition), then these will also be affected.

This issue affects:

Junos OS: * from 21.4 before 21.4R3-S4,

* from 22.1 before 22.1R3-S4,

* from 22.2 before 22.2R3-S2,

* from 22.3 before 22.3R2-S2, 22.3R3-S1,

* from 22.4 before 22.4R3,

* from 23.2 before 23.2R2.

Junos OS Evolved: * from 21.4-EVO before 21.4R3-S5-EVO,

* from 22.1-EVO before 22.1R3-S4-EVO,

* from 22.2-EVO before 22.2R3-S2-EVO,

* from 22.3-EVO before 22.3R2-S2-EVO, 22.3R3-S1-EVO,

* from 22.4-EVO before 22.4R3-EVO,

* from 23.2-EVO before 23.2R2-EVO.

This issue does not affect: * Junos OS versions prior to 21.4R1;

* Junos OS Evolved versions prior to 21.4R1-EVO.

Patch / fix

  • Juniper Networks Junos OS 21.4R3-S4, 22.1R3-S4, 22.2R3-S2, 22.3R2-S2, 22.3R3-S1, 22.4R3, 23.2R2
  • Juniper Networks Junos OS Evolved 21.4R3-S5-EVO, 22.1R3-S4-EVO, 22.2R3-S2-EVO, 22.3R2-S2-EVO, 22.3R3-S1-EVO, 22.4R3-EVO, 23.2R2-EVO

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 7.1 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L
CNA 4.0 7.1 CVSS:4.0/AV:A/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:X/R:X/V:X/RE:X/U:X

Affected products

  • Juniper Networks Junos OS
  • Juniper Networks Junos OS Evolved

Classification

Weakness
  • CWE-788 Access of Memory Location After End of Buffer
  • CWE-125 Out-of-bounds Read

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.