Vulnerability Monitor

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CVE-2021-0264


A vulnerability in the processing of traffic matching a firewall filter containing a syslog action in Juniper Networks Junos OS on MX Series with MPC10/MPC11 cards installed, PTX10003 and PTX10008 Series devices, will cause the line card to crash and restart, creating a Denial of Service (DoS). Continued receipt and processing of packets matching the firewall filter can create a sustained Denial of Service (DoS) condition. When traffic hits the firewall filter, configured on lo0 or any physical interface on the line card, containing a term with a syslog action (e.g. 'term <name> then syslog'), the affected line card will crash and restart, impacting traffic processing through the ports of the line card. This issue only affects MX Series routers with MPC10 or MPC11 line cards, and PTX10003 or PTX10008 Series packet transport routers. No other platforms or models of line cards are affected by this issue. Note: This issue has also been identified and described in technical service bulletin TSB17931 (login required). This issue affects: Juniper Networks Junos OS on MX Series: 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R3-S2; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R2-S2, 20.2R3; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R2. Juniper Networks Junos OS Evolved on PTX10003, PTX10008: All versions prior to 20.4R2-EVO. This issue does not affect Juniper Networks Junos OS versions prior to 19.3R1.


Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 5.9, indicating it can be exploited remotely over the network but requires specific conditions to be met without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 21 products from juniper, from juniper, from juniper and 18 others, 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

2021-04-22T20:15:09.810

Last Modified

2024-11-21T05:42:21.163

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 5.9 (MEDIUM)

CVSSv2 Vector

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

  • Access Vector: NETWORK
  • Access Complexity: LOW
  • Authentication: NONE
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: PARTIAL
Exploitability Score

10.0

Impact Score

2.9

Weaknesses
  • Type: Secondary
    CWE-703
  • Type: Primary
    CWE-755

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
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 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 20.1 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 20.2 Yes
Operating System juniper junos 20.3 Yes
Operating System juniper junos 20.3 Yes
Operating System juniper junos 20.4 Yes
Hardware juniper mx10 - No
Hardware juniper mx10000 - No
Hardware juniper mx10003 - No
Hardware juniper mx10008 - No
Hardware juniper mx10016 - No
Hardware juniper mx104 - No
Hardware juniper mx150 - No
Hardware juniper mx2008 - No
Hardware juniper mx2010 - No
Hardware juniper mx2020 - No
Hardware juniper mx204 - No
Hardware juniper mx240 - No
Hardware juniper mx40 - No
Hardware juniper mx480 - No
Hardware juniper mx5 - No
Hardware juniper mx80 - No
Hardware juniper mx960 - No
Operating System juniper junos_os_evolved 18.3 Yes
Operating System juniper junos_os_evolved 19.1 Yes
Operating System juniper junos_os_evolved 19.1 Yes
Operating System juniper junos_os_evolved 19.2 Yes
Operating System juniper junos_os_evolved 19.2 Yes
Operating System juniper junos_os_evolved 19.3 Yes
Operating System juniper junos_os_evolved 19.3 Yes
Operating System juniper junos_os_evolved 20.1 Yes
Operating System juniper junos_os_evolved 20.1 Yes
Operating System juniper junos_os_evolved 20.2 Yes
Operating System juniper junos_os_evolved 20.2 Yes
Operating System juniper junos_os_evolved 20.3 Yes
Operating System juniper junos_os_evolved 20.3 Yes
Operating System juniper junos_os_evolved 20.4 Yes
Hardware juniper ptx10003 - No
Hardware juniper ptx10008 - No

References

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.