high
7.5
CWE
125 770
Advisory Published
Updated

CVE-2021-0261: Junos OS: Denial of Service vulnerability in J-Web and web based (HTTP/HTTPS) services caused by a high number of specific requests

First published: Thu Apr 22 2021(Updated: )

A vulnerability in the HTTP/HTTPS service used by J-Web, Web Authentication, Dynamic-VPN (DVPN), Firewall Authentication Pass-Through with Web-Redirect, and Captive Portal allows an unauthenticated attacker to cause an extended Denial of Service (DoS) for these services by sending a high number of specific requests. This issue affects: Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S17 on EX Series; 12.3X48 versions prior to 12.3X48-D105 on SRX Series; 15.1 versions prior to 15.1R7-S8; 15.1X49 versions prior to 15.1X49-D230 on SRX Series; 16.1 versions prior to 16.1R7-S8; 17.4 versions prior to 17.4R2-S12, 17.4R3-S3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S6; 18.3 versions prior to 18.3R2-S4, 18.3R3-S3; 18.4 versions prior to 18.4R2-S5, 18.4R3-S4; 19.1 versions prior to 19.1R2-S2, 19.1R3-S2; 19.2 versions prior to 19.2R1-S5, 19.2R3; 19.3 versions prior to 19.3R2-S4, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2-S2, 19.4R3; 20.1 versions prior to 20.1R1-S3, 20.1R2; 20.2 versions prior to 20.2R1-S1, 20.2R2.

Credit: sirt@juniper.net

Affected SoftwareAffected VersionHow to fix
Junos OS Evolved=12.3
Junos OS Evolved=12.3-r1
Junos OS Evolved=12.3-r10
Junos OS Evolved=12.3-r10-s1
Junos OS Evolved=12.3-r10-s2
Junos OS Evolved=12.3-r11
Junos OS Evolved=12.3-r12
Junos OS Evolved=12.3-r12-s1
Junos OS Evolved=12.3-r12-s10
Junos OS Evolved=12.3-r12-s11
Junos OS Evolved=12.3-r12-s12
Junos OS Evolved=12.3-r12-s13
Junos OS Evolved=12.3-r12-s14
Junos OS Evolved=12.3-r12-s15
Junos OS Evolved=12.3-r12-s16
Junos OS Evolved=12.3-r12-s3
Junos OS Evolved=12.3-r12-s4
Junos OS Evolved=12.3-r12-s6
Junos OS Evolved=12.3-r12-s8
Juniper EX2300-24T
Juniper EX2300-C
Juniper EX3400
Juniper EX4300-24T
Juniper EX4400-24X
Juniper EX4600
Juniper EX4650
Juniper EX9200
Juniper EX9250
Junos OS Evolved=12.3x48
Junos OS Evolved=12.3x48-d10
Junos OS Evolved=12.3x48-d100
Junos OS Evolved=12.3x48-d15
Junos OS Evolved=12.3x48-d20
Junos OS Evolved=12.3x48-d25
Junos OS Evolved=12.3x48-d30
Junos OS Evolved=12.3x48-d35
Junos OS Evolved=12.3x48-d40
Junos OS Evolved=12.3x48-d45
Junos OS Evolved=12.3x48-d50
Junos OS Evolved=12.3x48-d51
Junos OS Evolved=12.3x48-d55
Junos OS Evolved=12.3x48-d60
Junos OS Evolved=12.3x48-d65
Junos OS Evolved=12.3x48-d66
Junos OS Evolved=12.3x48-d70
Junos OS Evolved=12.3x48-d75
Junos OS Evolved=12.3x48-d80
Junos OS Evolved=12.3x48-d85
Junos OS Evolved=12.3x48-d90
Junos OS Evolved=12.3x48-d95
Junos OS Evolved=15.1x49
Junos OS Evolved=15.1x49-d10
Junos OS Evolved=15.1x49-d100
Junos OS Evolved=15.1x49-d110
Junos OS Evolved=15.1x49-d120
Junos OS Evolved=15.1x49-d130
Junos OS Evolved=15.1x49-d131
Junos OS Evolved=15.1x49-d140
Junos OS Evolved=15.1x49-d15
Junos OS Evolved=15.1x49-d150
Junos OS Evolved=15.1x49-d160
Junos OS Evolved=15.1x49-d170
Junos OS Evolved=15.1x49-d180
Junos OS Evolved=15.1x49-d190
Junos OS Evolved=15.1x49-d20
Junos OS Evolved=15.1x49-d200
Junos OS Evolved=15.1x49-d210
Junos OS Evolved=15.1x49-d25
Junos OS Evolved=15.1x49-d30
Junos OS Evolved=15.1x49-d35
Junos OS Evolved=15.1x49-d40
Junos OS Evolved=15.1x49-d45
Junos OS Evolved=15.1x49-d50
Junos OS Evolved=15.1x49-d55
Junos OS Evolved=15.1x49-d60
Junos OS Evolved=15.1x49-d65
Junos OS Evolved=15.1x49-d70
Junos OS Evolved=15.1x49-d75
Junos OS Evolved=15.1x49-d80
Junos OS Evolved=15.1x49-d90
Juniper SRX1500
Juniper SRX300
Juniper SRX320
Juniper SRX340
Juniper SRX345
Juniper SRX380
Juniper SRX4100
Juniper SRX4200
Juniper SRX4600
Juniper SRX5400
Juniper SRX550
Juniper SRX5600
Juniper SRX5800
Junos OS Evolved=15.1
Junos OS Evolved=15.1-a1
Junos OS Evolved=15.1-f
Junos OS Evolved=15.1-f1
Junos OS Evolved=15.1-f2
Junos OS Evolved=15.1-f2-s1
Junos OS Evolved=15.1-f2-s2
Junos OS Evolved=15.1-f2-s3
Junos OS Evolved=15.1-f2-s4
Junos OS Evolved=15.1-f3
Junos OS Evolved=15.1-f4
Junos OS Evolved=15.1-f5
Junos OS Evolved=15.1-f5-s7
Junos OS Evolved=15.1-f6
Junos OS Evolved=15.1-f6-s1
Junos OS Evolved=15.1-f6-s10
Junos OS Evolved=15.1-f6-s12
Junos OS Evolved=15.1-f6-s2
Junos OS Evolved=15.1-f6-s3
Junos OS Evolved=15.1-f6-s4
Junos OS Evolved=15.1-f6-s5
Junos OS Evolved=15.1-f6-s6
Junos OS Evolved=15.1-f6-s7
Junos OS Evolved=15.1-f6-s8
Junos OS Evolved=15.1-f6-s9
Junos OS Evolved=15.1-f7
Junos OS Evolved=15.1-r
Junos OS Evolved=15.1-r1
Junos OS Evolved=15.1-r2
Junos OS Evolved=15.1-r3
Junos OS Evolved=15.1-r4
Junos OS Evolved=15.1-r4-s7
Junos OS Evolved=15.1-r4-s8
Junos OS Evolved=15.1-r4-s9
Junos OS Evolved=15.1-r5
Junos OS Evolved=15.1-r5-s1
Junos OS Evolved=15.1-r5-s3
Junos OS Evolved=15.1-r5-s5
Junos OS Evolved=15.1-r5-s6
Junos OS Evolved=15.1-r6
Junos OS Evolved=15.1-r6-s1
Junos OS Evolved=15.1-r6-s2
Junos OS Evolved=15.1-r6-s3
Junos OS Evolved=15.1-r6-s4
Junos OS Evolved=15.1-r6-s6
Junos OS Evolved=15.1-r7
Junos OS Evolved=15.1-r7-s1
Junos OS Evolved=15.1-r7-s2
Junos OS Evolved=15.1-r7-s3
Junos OS Evolved=15.1-r7-s4
Junos OS Evolved=15.1-r7-s5
Junos OS Evolved=15.1-r7-s6
Junos OS Evolved=15.1-r7-s7
Junos OS Evolved=16.1
Junos OS Evolved=16.1-r
Junos OS Evolved=16.1-r1
Junos OS Evolved=16.1-r2
Junos OS Evolved=16.1-r3
Junos OS Evolved=16.1-r3-s10
Junos OS Evolved=16.1-r3-s11
Junos OS Evolved=16.1-r3-s8
Junos OS Evolved=16.1-r4
Junos OS Evolved=16.1-r4-s12
Junos OS Evolved=16.1-r4-s2
Junos OS Evolved=16.1-r4-s3
Junos OS Evolved=16.1-r4-s4
Junos OS Evolved=16.1-r4-s6
Junos OS Evolved=16.1-r4-s8
Junos OS Evolved=16.1-r4-s9
Junos OS Evolved=16.1-r5
Junos OS Evolved=16.1-r5-s4
Junos OS Evolved=16.1-r6
Junos OS Evolved=16.1-r6-s1
Junos OS Evolved=16.1-r6-s3
Junos OS Evolved=16.1-r6-s4
Junos OS Evolved=16.1-r6-s6
Junos OS Evolved=16.1-r7
Junos OS Evolved=16.1-r7-s2
Junos OS Evolved=16.1-r7-s3
Junos OS Evolved=16.1-r7-s4
Junos OS Evolved=16.1-r7-s5
Junos OS Evolved=16.1-r7-s6
Junos OS Evolved=16.1-r7-s7
Junos OS Evolved=17.3
Junos OS Evolved=17.3-r1
Junos OS Evolved=17.3-r1-s1
Junos OS Evolved=17.3-r1-s4
Junos OS Evolved=17.3-r2
Junos OS Evolved=17.3-r2-s1
Junos OS Evolved=17.3-r2-s2
Junos OS Evolved=17.3-r2-s3
Junos OS Evolved=17.3-r2-s4
Junos OS Evolved=17.3-r2-s5
Junos OS Evolved=17.3-r3
Junos OS Evolved=17.3-r3
Junos OS Evolved=17.3-r3-s1
Junos OS Evolved=17.3-r3-s2
Junos OS Evolved=17.3-r3-s3
Junos OS Evolved=17.3-r3-s4
Junos OS Evolved=17.3-r3-s5
Junos OS Evolved=17.3-r3-s6
Junos OS Evolved=17.3-r3-s7
Junos OS Evolved=17.3-r3-s8
Junos OS Evolved=17.3-r3-s9
Junos OS Evolved=17.4
Junos OS Evolved=17.4-r1
Junos OS Evolved=17.4-r1-s1
Junos OS Evolved=17.4-r1-s2
Junos OS Evolved=17.4-r1-s3
Junos OS Evolved=17.4-r1-s4
Junos OS Evolved=17.4-r1-s5
Junos OS Evolved=17.4-r1-s6
Junos OS Evolved=17.4-r1-s7
Junos OS Evolved=17.4-r2
Junos OS Evolved=17.4-r2-s1
Junos OS Evolved=17.4-r2-s10
Junos OS Evolved=17.4-r2-s11
Junos OS Evolved=17.4-r2-s2
Junos OS Evolved=17.4-r2-s3
Junos OS Evolved=17.4-r2-s4
Junos OS Evolved=17.4-r2-s5
Junos OS Evolved=17.4-r2-s6
Junos OS Evolved=17.4-r2-s7
Junos OS Evolved=17.4-r2-s8
Junos OS Evolved=17.4-r2-s9
Junos OS Evolved=18.1
Junos OS Evolved=18.1-r1
Junos OS Evolved=18.1-r2
Junos OS Evolved=18.1-r2-s1
Junos OS Evolved=18.1-r2-s2
Junos OS Evolved=18.1-r2-s4
Junos OS Evolved=18.1-r3
Junos OS Evolved=18.1-r3-s1
Junos OS Evolved=18.1-r3-s10
Junos OS Evolved=18.1-r3-s2
Junos OS Evolved=18.1-r3-s3
Junos OS Evolved=18.1-r3-s4
Junos OS Evolved=18.1-r3-s5
Junos OS Evolved=18.1-r3-s6
Junos OS Evolved=18.1-r3-s7
Junos OS Evolved=18.1-r3-s8
Junos OS Evolved=18.1-r3-s9
Junos OS Evolved=18.2
Junos OS Evolved=18.2-r1
Junos OS Evolved=18.2-r1
Junos OS Evolved=18.2-r1-s2
Junos OS Evolved=18.2-r1-s3
Junos OS Evolved=18.2-r1-s4
Junos OS Evolved=18.2-r1-s5
Junos OS Evolved=18.2-r2
Junos OS Evolved=18.2-r2-s1
Junos OS Evolved=18.2-r2-s2
Junos OS Evolved=18.2-r2-s3
Junos OS Evolved=18.2-r2-s4
Junos OS Evolved=18.2-r2-s5
Junos OS Evolved=18.2-r2-s6
Junos OS Evolved=18.2-r2-s7
Junos OS Evolved=18.2-r3
Junos OS Evolved=18.2-r3-s1
Junos OS Evolved=18.2-r3-s2
Junos OS Evolved=18.2-r3-s3
Junos OS Evolved=18.2-r3-s4
Junos OS Evolved=18.2-r3-s5
Junos OS Evolved=18.3
Junos OS Evolved=18.3-r1
Junos OS Evolved=18.3-r1-s1
Junos OS Evolved=18.3-r1-s2
Junos OS Evolved=18.3-r1-s3
Junos OS Evolved=18.3-r1-s4
Junos OS Evolved=18.3-r1-s5
Junos OS Evolved=18.3-r1-s6
Junos OS Evolved=18.3-r2
Junos OS Evolved=18.3-r2-s1
Junos OS Evolved=18.3-r2-s2
Junos OS Evolved=18.3-r2-s3
Junos OS Evolved=18.3-r3
Junos OS Evolved=18.3-r3-s1
Junos OS Evolved=18.3-r3-s2
Junos OS Evolved=18.4
Junos OS Evolved=18.4-r1
Junos OS Evolved=18.4-r1-s1
Junos OS Evolved=18.4-r1-s2
Junos OS Evolved=18.4-r1-s3
Junos OS Evolved=18.4-r1-s4
Junos OS Evolved=18.4-r1-s5
Junos OS Evolved=18.4-r1-s6
Junos OS Evolved=18.4-r1-s7
Junos OS Evolved=18.4-r2
Junos OS Evolved=18.4-r2-s1
Junos OS Evolved=18.4-r2-s2
Junos OS Evolved=18.4-r2-s3
Junos OS Evolved=18.4-r2-s4
Junos OS Evolved=18.4-r3
Junos OS Evolved=18.4-r3-s1
Junos OS Evolved=18.4-r3-s2
Junos OS Evolved=18.4-r3-s3
Junos OS Evolved=19.1
Junos OS Evolved=19.1-r1
Junos OS Evolved=19.1-r1-s1
Junos OS Evolved=19.1-r1-s2
Junos OS Evolved=19.1-r1-s3
Junos OS Evolved=19.1-r1-s4
Junos OS Evolved=19.1-r1-s5
Junos OS Evolved=19.1-r2
Junos OS Evolved=19.1-r2-s1
Junos OS Evolved=19.1-r3
Junos OS Evolved=19.1-r3-s1
Junos OS Evolved=19.2
Junos OS Evolved=19.2-r1
Junos OS Evolved=19.2-r1-s1
Junos OS Evolved=19.2-r1-s2
Junos OS Evolved=19.2-r1-s3
Junos OS Evolved=19.2-r1-s4
Junos OS Evolved=19.2-r2
Junos OS Evolved=19.2-r2-s1
Junos OS Evolved=19.3
Junos OS Evolved=19.3-r1
Junos OS Evolved=19.3-r1-s1
Junos OS Evolved=19.3-r2
Junos OS Evolved=19.3-r2-s1
Junos OS Evolved=19.3-r2-s2
Junos OS Evolved=19.3-r2-s3
Junos OS Evolved=19.4-r1
Junos OS Evolved=19.4-r1-s1
Junos OS Evolved=19.4-r1-s2
Junos OS Evolved=19.4-r2
Junos OS Evolved=19.4-r2-s1
Junos OS Evolved=20.1-r1
Junos OS Evolved=20.1-r1-s1
Junos OS Evolved=20.1-r1-s2
Junos OS Evolved=20.2-r1

Remedy

The following software releases have been updated to resolve this specific issue: 12.3R12-S17, 12.3X48-D105, 15.1R7-S8, 15.1X49-D230, 16.1R7-S8, 17.4R2-S12, 17.4R3-S3, 18.1R3-S11, 18.2R3-S6, 18.3R2-S4, 18.3R3-S3, 18.4R2-S5, 18.4R3-S4, 19.1R2-S2, 19.1R3-S2, 19.2R1-S5, 19.2R3, 19.3R2-S4, 19.3R3, 19.4R1-S3, 19.4R2-S2, 19.4R3, 20.1R1-S3, 20.1R2, 20.2R1-S1, 20.2R2, 20.3R1, and all subsequent releases.

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2021-0261?

    CVE-2021-0261 has a high severity as it allows an unauthenticated attacker to cause an extended Denial of Service for affected Juniper JUNOS services.

  • How do I fix CVE-2021-0261?

    To fix CVE-2021-0261, you should upgrade to the patched versions of Juniper JUNOS as specified in the security advisory.

  • What versions of Juniper JUNOS are affected by CVE-2021-0261?

    CVE-2021-0261 affects various versions of Juniper JUNOS including 12.3 and certain 15.x and 16.x versions.

  • Is there a workaround for CVE-2021-0261?

    No official workaround is available for CVE-2021-0261; updating to a fixed version is recommended.

  • What impact does CVE-2021-0261 have on my network?

    CVE-2021-0261 can lead to a prolonged Denial of Service, disrupting availability for critical services like Web Authentication and Dynamic-VPN.

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