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CVE-2021-0283

Junos OS: Upon receipt of specific sequences of genuine packets destined to the device the kernel will crash and restart (vmcore)

High7.5EPSS 0.99%
Published
Updated
Reserved
Assigned by
juniper

Description

A buffer overflow vulnerability in the TCP/IP stack of Juniper Networks Junos OS allows an attacker to send specific sequences of packets to the device thereby causing a Denial of Service (DoS). By repeatedly sending these sequences of packets to the device, an attacker can sustain the Denial of Service (DoS) condition. The device will abnormally shut down as a result of these sent packets. A potential indicator of compromise will be the following message in the log files: "eventd[13955]: SYSTEM_ABNORMAL_SHUTDOWN: System abnormally shut down" These issue are only triggered by traffic destined to the device. Transit traffic will not trigger these issues. This issue affects: Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S19; 15.1 versions prior to 15.1R7-S10; 16.1 version 16.1R1 and later versions; 16.2 version 16.2R1 and later versions; 17.1 version 17.1R1 and later versions; 17.2 version 17.2R1 and later versions; 17.3 versions prior to 17.3R3-S12; 17.4 version 17.4R1 and later versions; 18.1 versions prior to 18.1R3-S13; 18.2 version 18.2R1 and later versions; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R2-S9, 18.4R3-S9; 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-S7, 19.3R3-S3; 19.4 versions prior to 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; 20.4 versions prior to 20.4R2-S1, 20.4R3; 21.1 versions prior to 21.1R1-S1, 21.1R2; 21.2 versions prior to 21.2R1-S1, 21.2R2.

Timeline

  1. ID reserved

    By juniper

  2. · 9 months later

    Published

  3. · 3 years later

    Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2021-0283, by who scored it
Scored byCVSSScoreVector
juniperCNA (assigner)3.1High7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVDNVD · Modified3.1High7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (exploitation in 30 days)
0.99% · top 37% of all CVEs (7 Nov 2026)
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

Affected products

  • Juniper Networks · Junos OS

    • affected 12.3 – < 12.3R12-S19
    • affected 15.1 – < 15.1R7-S10
    • affected 16.1R1 – < 16.1*
    • affected 16.2R1 – < 16.2*
    • affected 17.1R1 – < 17.1*
    • affected 17.2R1 – < 17.2*
    • affected 17.3 – < 17.3R3-S12
    • affected 17.4R1 – < 17.4*
    • affected 18.1 – < 18.1R3-S13
    • affected 18.2R1 – < 18.2*
    • affected 18.3 – < 18.3R3-S5
    • affected 18.4 – < 18.4R2-S9, 18.4R3-S9
    • affected 19.1 – < 19.1R3-S6
    • affected 19.2 – < 19.2R1-S7, 19.2R3-S3
    • affected 19.3 – < 19.3R2-S7, 19.3R3-S3
    • affected 19.4 – < 19.4R3-S5
    • affected 20.1 – < 20.1R2-S2, 20.1R3-S1
    • affected 20.2 – < 20.2R3-S2
    • affected 20.3 – < 20.3R3
    • affected 20.4 – < 20.4R2-S1, 20.4R3
    • affected 21.1 – < 21.1R1-S1, 21.1R2
    • affected 21.2 – < 21.2R1-S1, 21.2R2

What to do

Solution: The following software releases have been updated to resolve this specific issue: 12.3R12-S19, 15.1R7-S10, 17.3R3-S12, 18.1R3-S13, 18.3R3-S5, 18.4R2-S9, 18.4R3-S9, 19.1R3-S6, 19.2R1-S7, 19.2R3-S3, 19.3R2-S7, 19.3R3-S3, 19.4R3-S5, 20.1R2-S2, 20.1R3-S1, 20.2R3-S2, 20.3R3, 20.4R2-S1, 20.4R3, 21.1R1-S1, 21.1R2, 21.2R1-S1, 21.2R2, 21.3R1, and all subsequent releases.

Workaround: There are no available workarounds for this issue. To reduce the risk of exploitation of this issue, use access lists or firewall filters to limit access to the device to only trusted administrative networks, hosts and users.

Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability. Juniper SIRT is aware of this occurring in production. In all reported cases the Junos device was not the intended target of the attack, but this vulnerability was still triggered.

References (1)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .