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Fencer Vulns
medium 6.5

CVE-2024-39557 json

Junos OS Evolved: MAC table changes cause a memory leak

published 2024-07-10 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-38083

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

An Uncontrolled Resource Consumption vulnerability in the

Layer 2 Address Learning Daemon (l2ald)

of Juniper Networks Junos OS Evolved allows an unauthenticated, adjacent attacker to cause a memory leak, eventually exhausting all system memory, leading to a system crash and Denial of Service (DoS).

Certain MAC table updates cause a small amount of memory to leak.  Once memory utilization reaches its limit, the issue will result in a system crash and restart.

To identify the issue, execute the CLI command:

user@device> show platform application-info allocations app l2ald-agent EVL Object Allocation Statistics:

Node   Application     Context Name                               Live   Allocs   Fails     Guids re0   l2ald-agent               net::juniper::rtnh::L2Rtinfo       1069096 1069302   0         1069302 re0   l2ald-agent               net::juniper::rtnh::NHOpaqueTlv     114     195       0         195

This issue affects Junos OS Evolved:

* All versions before 21.4R3-S8-EVO,

* from 22.2-EVO before 22.2R3-S4-EVO, * from 22.3-EVO before 22.3R3-S3-EVO, * from 22.4-EVO before 22.4R3-EVO, * from 23.2-EVO before 23.2R2-EVO.

Patch / fix

  • Juniper Networks Junos OS Evolved 21.4R3-S8-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO, 22.4R3-EVO, 23.2R2-EVO

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 15% 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/R:A
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:A/V:X/RE:X/U:X

Affected products

  • Juniper Networks Junos OS Evolved

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

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.