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CVE-2021-0242

A vulnerability due to the improper handling of direct memory access (DMA) buffers on EX4300 switches on Juniper Networks Junos OS allows an attacker sending specific unicast frames to trigger a Denial of Service (DoS) condition by exhausting DMA buffers, causing the FPC to crash and the device to restart. The DMA buffer leak is seen when receiving these specific, valid unicast frames on an interface without Layer 2 Protocol Tunneling (L2PT) or dot1x configured. Interfaces with either L2PT or dot1x configured are not vulnerable to this issue. When this issue occurs, DMA buffer usage keeps increasing and the following error log messages may be observed: Apr 14 14:29:34.360 /kernel: pid 64476 (pfex_junos), uid 0: exited on signal 11 (core dumped) Apr 14 14:29:33.790 init: pfe-manager (PID 64476) terminated by signal number 11. Core dumped! The DMA buffers on the FPC can be monitored by the executing vty command 'show heap': ID Base Total(b) Free(b) Used(b) % Name -- ---------- ----------- ----------- ----------- --- ----------- 0 4a46000 268435456 238230496 30204960 11 Kernel 1 18a46000 67108864 17618536 49490328 73 Bcm_sdk 2 23737000 117440512 18414552 99025960 84 DMA buf <<<<< keeps increasing 3 2a737000 16777216 16777216 0 0 DMA desc This issue affects Juniper Networks Junos OS on the EX4300: 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R2-S13, 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S7; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S7; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S4; 19.2 versions prior to 19.2R1-S6, 19.2R3-S2; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R2-S3, 19.4R3-S1; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R2-S1, 20.2R3; 20.3 versions prior to 20.3R1-S1, 20.3R2.

Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 6.5, indicating it requires adjacent network access with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 2 products from juniper, from juniper organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2021-04-22T20:15:09.057

Last Modified

2024-11-21T05:42:17.677

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 6.5 (MEDIUM)

CVSSv2 Vector

AV:A/AC:L/Au:N/C:N/I:N/A:C

Access Vector: ADJACENT_NETWORK
Access Complexity: LOW
Authentication: NONE
Confidentiality Impact: NONE
Integrity Impact: NONE
Availability Impact: COMPLETE

Exploitability Score

6.5

Impact Score

6.9

Weaknesses

Type: Secondary
CWE-119
CWE-241
Type: Primary
CWE-770

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.3	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	17.4	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.1	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.2	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.3	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	18.4	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.1	Yes
Operating System	juniper	junos	19.2	Yes
Operating System	juniper	junos	19.2	Yes
Operating System	juniper	junos	19.2	Yes
Operating System	juniper	junos	19.2	Yes
Operating System	juniper	junos	19.2	Yes
Operating System	juniper	junos	19.2	Yes
Operating System	juniper	junos	19.2	Yes
Operating System	juniper	junos	19.2	Yes
Operating System	juniper	junos	19.2	Yes
Operating System	juniper	junos	19.2	Yes
Operating System	juniper	junos	19.2	Yes
Operating System	juniper	junos	19.3	Yes
Operating System	juniper	junos	19.3	Yes
Operating System	juniper	junos	19.3	Yes
Operating System	juniper	junos	19.3	Yes
Operating System	juniper	junos	19.3	Yes
Operating System	juniper	junos	19.3	Yes
Operating System	juniper	junos	19.3	Yes
Operating System	juniper	junos	19.3	Yes
Operating System	juniper	junos	19.3	Yes
Operating System	juniper	junos	19.3	Yes
Operating System	juniper	junos	19.4	Yes
Operating System	juniper	junos	19.4	Yes
Operating System	juniper	junos	19.4	Yes
Operating System	juniper	junos	19.4	Yes
Operating System	juniper	junos	19.4	Yes
Operating System	juniper	junos	19.4	Yes
Operating System	juniper	junos	19.4	Yes
Operating System	juniper	junos	20.1	Yes
Operating System	juniper	junos	20.1	Yes
Operating System	juniper	junos	20.1	Yes
Operating System	juniper	junos	20.1	Yes
Operating System	juniper	junos	20.1	Yes
Operating System	juniper	junos	20.2	Yes
Operating System	juniper	junos	20.2	Yes
Operating System	juniper	junos	20.2	Yes
Operating System	juniper	junos	20.2	Yes
Operating System	juniper	junos	20.2	Yes
Operating System	juniper	junos	20.3	Yes
Hardware	juniper	ex4300	-	No

References

https://kb.juniper.net/JSA11135 Vendor Advisory ([email protected])
https://kb.juniper.net/JSA11135 Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For juniper's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.