Home/CVE/Juniper Networks Junos OS uses the 128.0.0.0/2 subnet for internal communications between the RE and PFEs. It was discov
CVE

CVE-2021-31371

Juniper Networks Junos OS uses the 128.0.0.0/2 subnet for internal communications between the RE and PFEs. It was discov

Juniper Networks Junos OS uses the 128.0.0.0/2 subnet for internal communications between the RE and PFEs. It was discovered that packets utilizing these IP addresses may egress an QFX5000 Series switch, leaking configuration information such as heartbeats, kernel versions, etc. out to the Internet, leading to an information exposure vulnerability. This issue affects Juniper Networks Junos OS on QFX5110, QFX5120, QFX5200, QFX5210 Series, and QFX5100 with QFX 5e Series image installed: All versions prior to 17.3R3-S12.

18.1 versions prior to 18.1R3-S13.

18.3 versions prior to 18.3R3-S5.

19.1 versions prior to 19.1R3-S6.

19.2 versions prior to 19.2R1-S7, 19.2R3-S3.

19.3 versions prior to 19.3R2-S6, 19.3R3-S3.

19.4 versions prior to 19.4R1-S4, 19.4R3-S5.

20.1 versions prior to 20.1R2-S2, 20.1R3-S1.

20.2 versions prior to 20.2R3-S2.

20.3 versions prior to 20.3R3-S1.

20.4 versions prior to 20.4R2-S1, 20.4R3.

21.1 versions prior to 21.1R1-S1, 21.1R2;.

MEDIUM · CVSS 5.3 EPSS 0.00215
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
▤

Affected Products & Versions

2
juniper junos<= 17.2
juniper junosall versions
▣

Scoring & Timeline

5.3
MEDIUM · CVSS v3.1 · sirt@juniper.net
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD19 Oct 2021 · 07:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://kb.juniper.net/JSA11236MitigationVendor Advisory
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