CVE-2021-0244

Junos OS: A race condition in the storm control profile may allow an attacker to cause a Denial of Service condition

HIGH

7.4

CVSS Score

Published: April 22, 2021 at 07:37 PM UTC

Updated: June 17, 2026 at 03:29 AM UTC

23 products affected across 2 vendorsJunosSRX5600SRX5800

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Severity

HIGH7.4

Exploit prediction

EPSS 0.6%

Description

A signal handler race condition exists in the Layer 2 Address Learning Daemon (L2ALD) of Juniper Networks Junos OS due to the absence of a specific protection mechanism to avoid a race condition which may allow an attacker to bypass the storm-control feature on devices. This issue is a corner case and only occurs during specific actions taken by an administrator of a device under certain specifics actions which triggers the event. The event occurs less frequently on devices which are not configured with Virtual Chassis configurations, and more frequently on devices configured in Virtual Chassis configurations. This issue is not specific to any particular Junos OS platform. An Indicator of Compromise (IoC) may be seen by reviewing log files for the following error message seen by executing the following show statement: show log messages | grep storm Result to look for: /kernel: GENCFG: op 58 (Storm Control Blob) failed; err 1 (Unknown) This issue affects: Juniper Networks Junos OS: 14.1X53 versions prior to 14.1X53-D49 on EX Series; 15.1 versions prior to 15.1R7-S6; 15.1X49 versions prior to 15.1X49-D191, 15.1X49-D200 on SRX Series; 16.1 versions prior to 16.1R7-S7; 16.2 versions prior to 16.2R2-S11, 16.2R3; 17.1 versions prior to 17.1R2-S11, 17.1R3; 17.2 versions prior to 17.2R2-S8, 17.2R3-S3; 17.3 versions prior to 17.3R2-S5, 17.3R3-S7; 17.4 versions prior to 17.4R2-S9, 17.4R3; 18.1 versions prior to 18.1R3-S5; 18.2 versions prior to 18.2R2-S6, 18.2R3; 18.3 versions prior to 18.3R1-S7, 18.3R2-S3, 18.3R3; 18.4 versions prior to 18.4R1-S5, 18.4R2; 19.1 versions prior to 19.1R1-S4, 19.1R2.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Junos · Juniper Networks

95%

14.1X53 ≤ v < 14.1X53-D4915.1 ≤ v < 15.1R7-S615.1X49 ≤ v < 15.1X49-D191, 15.1X49-D20016.1 ≤ v < 16.1R7-S716.2 ≤ v < 16.2R2-S11, 16.2R317.1 ≤ v < 17.1R2-S11, 17.1R317.2 ≤ v < 17.2R2-S8, 17.2R3-S317.3 ≤ v < 17.3R2-S5, 17.3R3-S717.4 ≤ v < 17.4R2-S9, 17.4R318.1 ≤ v < 18.1R3-S518.2 ≤ v < 18.2R2-S6, 18.2R318.3 ≤ v < 18.3R1-S7, 18.3R2-S3, 18.3R318.4 ≤ v < 18.4R1-S5, 18.4R219.1 ≤ v < 19.1R1-S4, 19.1R214.1X5314.1x5314.1x53 d10 14.1x53 d15 14.1x53 d16 14.1x53 d20 14.1x53 d25 14.1x53 d26 14.1x53 d27 14.1x53 d30 14.1x53 d34 14.1x53 d35 14.1x53 d38 14.1x53 d40 14.1x53 d42 14.1x53 d43 14.1x53 d44 14.1x53 d45 14.1x53 d4614.1x53 d4714.1x53 d48 15.1 15.1 a1 15.1 f 15.1 f1 15.1 f2 15.1 f2-s1 15.1 f2-s2 15.1 f2-s3 15.1 f2-s4 15.1 f3 15.1 f4 15.1 f5 15.1 f5-s7 15.1 f6 15.1 f6-s1 15.1 f6-s10 15.1 f6-s12 15.1 f6-s2 15.1 f6-s3 15.1 f6-s4 15.1 f6-s5 15.1 f6-s6 15.1 f6-s7 15.1 f6-s8 15.1 f6-s9 15.1 f7 15.1 r 15.1 r1 15.1 r2 15.1 r3 15.1 r4 15.1 r4-s7 15.1 r4-s8 15.1 r4-s9 15.1 r5 15.1 r5-s1 15.1 r5-s3 15.1 r5-s5 15.1 r5-s6 15.1 r6 15.1 r6-s1 15.1 r6-s2 15.1 r6-s3 15.1 r6-s4 15.1 r6-s6 15.1 r7 15.1 r7-s1 15.1 r7-s2 15.1 r7-s3 15.1 r7-s4 15.1 r7-s5 15.1X4915.1x4915.1x49 d10 15.1x49 d100 15.1x49 d110 15.1x49 d120 15.1x49 d13015.1x49 d13115.1x49 d140 15.1x49 d15 15.1x49 d150 15.1x49 d160 15.1x49 d170 15.1x49 d180 15.1x49 d190 15.1x49 d20 15.1x49 d25 15.1x49 d30 15.1x49 d35 15.1x49 d40 15.1x49 d45 15.1x49 d50 15.1x49 d55 15.1x49 d60 15.1x49 d65 15.1x49 d70 15.1x49 d75 15.1x49 d80 15.1x49 d90 16.1 16.1 r 16.1 r1 16.1 r2 16.1 r3 16.1 r3-s10 16.1 r3-s11 16.1 r3-s8 16.1 r4 16.1 r4-s12 16.1 r4-s2 16.1 r4-s3 16.1 r4-s4 16.1 r4-s6 16.1 r4-s8 16.1 r4-s9 16.1 r5 16.1 r5-s4 16.1 r6 16.1 r6-s1 16.1 r6-s3 16.1 r6-s4 16.1 r6-s6 16.1 r7 16.1 r7-s2 16.1 r7-s3 16.1 r7-s4 16.1 r7-s5 16.1 r7-s6 16.2 16.2 r1 16.2 r1-s6 16.2 r2 16.2 r2-s1 16.2 r2-s10 16.2 r2-s2 16.2 r2-s5 16.2 r2-s6 16.2 r2-s7 16.2 r2-s8 16.2 r2-s9 17.1 17.1 r1 17.1 r1-s7 17.1 r2 17.1 r2-s1 17.1 r2-s10 17.1 r2-s2 17.1 r2-s3 17.1 r2-s4 17.1 r2-s5 17.1 r2-s6 17.1 r2-s7 17.1 r2-s8 17.1 r2-s9 17.2 17.2 r1 17.2 r1-s1 17.2 r1-s2 17.2 r1-s3 17.2 r1-s4 17.2 r1-s5 17.2 r1-s6 17.2 r1-s7 17.2 r1-s8 17.2 r2 17.2 r2-s11 17.2 r2-s4 17.2 r2-s6 17.2 r2-s7 17.2 r3 17.2 r3-s1 17.2 r3-s2 17.3 17.3 r1 17.3 r1-s1 17.3 r1-s4 17.3 r2 17.3 r2-s1 17.3 r2-s2 17.3 r2-s3 17.3 r2-s4 17.3 r3 17.3 r3-s1 17.3 r3-s10 17.3 r3-s2 17.3 r3-s3 17.3 r3-s4 17.3 r3-s5 17.3 r3-s6 17.4 17.4 r1 17.4 r1-s1 17.4 r1-s2 17.4 r1-s3 17.4 r1-s4 17.4 r1-s5 17.4 r1-s6 17.4 r1-s7 17.4 r2 17.4 r2-s1 17.4 r2-s2 17.4 r2-s3 17.4 r2-s4 17.4 r2-s5 17.4 r2-s6 17.4 r2-s7 17.4 r2-s8 18.1 18.1 r1 18.1 r2 18.1 r2-s1 18.1 r2-s2 18.1 r2-s4 18.1 r3 18.1 r3-s1 18.1 r3-s2 18.1 r3-s3 18.1 r3-s4 18.2 18.2 r1 18.2 r1-s2 18.2 r1-s3 18.2 r1-s4 18.2 r1-s5 18.2 r2 18.2 r2-s1 18.2 r2-s2 18.2 r2-s3 18.2 r2-s4 18.2 r2-s5 18.3 18.3 r1 18.3 r1-s1 18.3 r1-s2 18.3 r1-s3 18.3 r1-s4 18.3 r1-s5 18.3 r1-s6 18.3 r2 18.3 r2-s1 18.3 r2-s2 18.4 19.1 19.1 r1 19.1 r1-s1 19.1 r1-s2 19.1 r1-s3

Affected range stops below 14.1X53-D49, so it looks safe — our inference, not a vendor statement

Affected range stops below 15.1R7-S6, so it looks safe — our inference, not a vendor statement

Affected range stops below 15.1X49-D191, 15.1X49-D200, so it looks safe — our inference, not a vendor statement

Affected range stops below 16.1R7-S7, so it looks safe — our inference, not a vendor statement

Affected range stops below 16.2R2-S11, 16.2R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 17.1R2-S11, 17.1R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 17.2R2-S8, 17.2R3-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 17.3R2-S5, 17.3R3-S7, so it looks safe — our inference, not a vendor statement

Affected range stops below 17.4R2-S9, 17.4R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.1R3-S5, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.2R2-S6, 18.2R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.3R1-S7, 18.3R2-S3, 18.3R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.4R1-S5, 18.4R2, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.1R1-S4, 19.1R2, so it looks safe — our inference, not a vendor statement

juniper-ex2300 (environment) · juniper-ex2300-c (environment) · juniper-ex3400 (environment) · juniper-ex4300 (environment) · juniper-ex4400 (environment) · juniper-ex4600 (environment) · juniper-ex4650 (environment) · juniper-ex9200 (environment) · juniper-ex9250 (environment) · juniper-srx1500 (environment) · juniper-srx300 (environment) · juniper-srx320 (environment) · juniper-srx340 (environment) · juniper-srx345 (environment) · juniper-srx380 (environment) · juniper-srx4100 (environment) · juniper-srx4200 (environment) · juniper-srx4600 (environment) · juniper-srx5400 (environment) · juniper-srx550 (environment) · juniper-srx5600 (environment) · juniper-srx5800 (environment)

Ex2300 · Juniperdevice

80%

All versions

Ex2300-C · Juniperdevice

80%

All versions

Ex3400 · Juniperdevice

80%

All versions

Ex4300 · Juniperdevice

80%

All versions