{"id":"CVE-2020-1662","state":"PUBLISHED","title":"Junos OS and Junos OS Evolved: RPD crash due to BGP session flapping.","description":"On Juniper Networks Junos OS and Junos OS Evolved devices, BGP session flapping can lead to a routing process daemon (RPD) crash and restart, limiting the attack surface to configured BGP peers. This issue only affects devices with BGP damping in combination with accepted-prefix-limit configuration. When the issue occurs the following messages will appear in the /var/log/messages: rpd[6046]: %DAEMON-4-BGP_PREFIX_THRESH_EXCEEDED: XXXX (External AS x): Configured maximum accepted prefix-limit threshold(1800) exceeded for inet6-unicast nlri: 1984 (instance master) rpd[6046]: %DAEMON-3-BGP_CEASE_PREFIX_LIMIT_EXCEEDED: 2001:x:x:x::2 (External AS x): Shutting down peer due to exceeding configured maximum accepted prefix-limit(2000) for inet6-unicast nlri: 2001 (instance master) rpd[6046]: %DAEMON-4: bgp_rt_maxprefixes_check_common:9284: NOTIFICATION sent to 2001:x:x:x::2 (External AS x): code 6 (Cease) subcode 1 (Maximum Number of Prefixes Reached) AFI: 2 SAFI: 1 prefix limit 2000 kernel: %KERN-5: mastership_relinquish_on_process_exit: RPD crashed on master RE. Sending SIGUSR2 to chassisd (5612:chassisd) to trigger RE switchover This issue affects: Juniper Networks Junos OS: 17.2R3-S3; 17.3 version 17.3R3-S3 and later versions, prior to 17.3R3-S8; 17.4 version 17.4R2-S4, 17.4R3 and later versions, prior to 17.4R2-S10, 17.4R3-S2; 18.1 version 18.1R3-S6 and later versions, prior to 18.1R3-S10; 18.2 version 18.2R3 and later versions, prior to 18.2R3-S4; 18.2X75 version 18.2X75-D50, 18.2X75-D60 and later versions, prior to 18.2X75-D53, 18.2X75-D65; 18.3 version 18.3R2 and later versions, prior to 18.3R2-S4, 18.3R3-S2; 18.4 version 18.4R2 and later versions, prior to 18.4R2-S5, 18.4R3-S2; 19.1 version 19.1R1 and later versions, prior to 19.1R2-S2, 19.1R3-S1; 19.2 version 19.2R1 and later versions, prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2; 20.1 versions prior to 20.1R1-S2, 20.1R2. Juniper Networks Junos OS Evolved prior to 20.1R2-EVO. This issue does not affect Juniper Networks Junos OS versions prior to 17.2R3-S3.","publishedAt":"2020-10-16T20:31:26.882Z","updatedAt":"2024-09-16T19:04:48.478Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"juniper"},"assigner":"juniper","products":["Juniper Networks Junos OS","Juniper Networks Junos OS Evolved"],"affected":[{"vendor":"Juniper Networks","product":"Junos OS","versions":[{"version":"17.2R3-S3","status":"affected"},{"version":"unspecified","status":"unaffected","lessThan":"17.2R3-S3","versionType":"custom"},{"version":"17.3R3-S3","status":"affected","lessThan":"17.3*","changes":[{"at":"17.3R3-S8","status":"unaffected"}],"versionType":"custom"},{"version":"17.4R2-S4, 17.4R3","status":"affected","lessThan":"17.4*","changes":[{"at":"17.4R2-S10, 17.4R3-S2","status":"unaffected"}],"versionType":"custom"},{"version":"18.1R3-S6","status":"affected","lessThan":"18.1*","changes":[{"at":"18.1R3-S10","status":"unaffected"}],"versionType":"custom"},{"version":"18.2R3","status":"affected","lessThan":"18.2*","changes":[{"at":"18.2R3-S4","status":"unaffected"}],"versionType":"custom"},{"version":"18.2X75-D50, 18.2X75-D60","status":"affected","lessThan":"18.2X75*","changes":[{"at":"18.2X75-D53, 18.2X75-D65","status":"unaffected"}],"versionType":"custom"},{"version":"18.3R2","status":"affected","lessThan":"18.3*","changes":[{"at":"18.3R2-S4, 18.3R3-S2","status":"unaffected"}],"versionType":"custom"},{"version":"18.4R2","status":"affected","lessThan":"18.4*","changes":[{"at":"18.4R2-S5, 18.4R3-S2","status":"unaffected"}],"versionType":"custom"},{"version":"19.1R1","status":"affected","lessThan":"19.1*","changes":[{"at":"19.1R2-S2, 19.1R3-S1","status":"unaffected"}],"versionType":"custom"},{"version":"19.2R1","status":"affected","lessThan":"19.2*","changes":[{"at":"19.2R1-S5, 19.2R2","status":"unaffected"}],"versionType":"custom"},{"version":"19.3","status":"affected","lessThan":"19.3R2-S3, 19.3R3","versionType":"custom"},{"version":"19.4","status":"affected","lessThan":"19.4R1-S3, 19.4R2","versionType":"custom"},{"version":"20.1","status":"affected","lessThan":"20.1R1-S2, 20.1R2","versionType":"custom"}]},{"vendor":"Juniper Networks","product":"Junos OS Evolved","versions":[{"version":"19.4-EVO","status":"affected"},{"version":"20.1-EVO","status":"affected","lessThan":"20.1R2-EVO","versionType":"custom"}]}],"references":["https://kb.juniper.net/JSA11059"],"weaknesses":["CWE-20"],"ingestedAt":"2026-10-29T19:46:49.649Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2020/1xxx/CVE-2020-1662.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2020-1662","state":"PUBLISHED","datePublished":"2020-10-16T20:31:26.882Z","dateUpdated":"2024-09-16T19:04:48.478Z","assignerShortName":"juniper","assignerOrgId":"8cbe9d5a-a066-4c94-8978-4b15efeae968","dateReserved":"2019-11-04T00:00:00.000Z"},"containers":{"cna":{"title":"Junos OS and Junos OS Evolved: RPD crash due to BGP session flapping.","descriptions":[{"lang":"en","value":"On Juniper Networks Junos OS and Junos OS Evolved devices, BGP session flapping can lead to a routing process daemon (RPD) crash and restart, limiting the attack surface to configured BGP peers. This issue only affects devices with BGP damping in combination with accepted-prefix-limit configuration. When the issue occurs the following messages will appear in the /var/log/messages: rpd[6046]: %DAEMON-4-BGP_PREFIX_THRESH_EXCEEDED: XXXX (External AS x): Configured maximum accepted prefix-limit threshold(1800) exceeded for inet6-unicast nlri: 1984 (instance master) rpd[6046]: %DAEMON-3-BGP_CEASE_PREFIX_LIMIT_EXCEEDED: 2001:x:x:x::2 (External AS x): Shutting down peer due to exceeding configured maximum accepted prefix-limit(2000) for inet6-unicast nlri: 2001 (instance master) rpd[6046]: %DAEMON-4: bgp_rt_maxprefixes_check_common:9284: NOTIFICATION sent to 2001:x:x:x::2 (External AS x): code 6 (Cease) subcode 1 (Maximum Number of Prefixes Reached) AFI: 2 SAFI: 1 prefix limit 2000 kernel: %KERN-5: mastership_relinquish_on_process_exit: RPD crashed on master RE. Sending SIGUSR2 to chassisd (5612:chassisd) to trigger RE switchover This issue affects: Juniper Networks Junos OS: 17.2R3-S3; 17.3 version 17.3R3-S3 and later versions, prior to 17.3R3-S8; 17.4 version 17.4R2-S4, 17.4R3 and later versions, prior to 17.4R2-S10, 17.4R3-S2; 18.1 version 18.1R3-S6 and later versions, prior to 18.1R3-S10; 18.2 version 18.2R3 and later versions, prior to 18.2R3-S4; 18.2X75 version 18.2X75-D50, 18.2X75-D60 and later versions, prior to 18.2X75-D53, 18.2X75-D65; 18.3 version 18.3R2 and later versions, prior to 18.3R2-S4, 18.3R3-S2; 18.4 version 18.4R2 and later versions, prior to 18.4R2-S5, 18.4R3-S2; 19.1 version 19.1R1 and later versions, prior to 19.1R2-S2, 19.1R3-S1; 19.2 version 19.2R1 and later versions, prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2; 20.1 versions prior to 20.1R1-S2, 20.1R2. Juniper Networks Junos OS Evolved prior to 20.1R2-EVO. This issue does not affect Juniper Networks Junos OS versions prior to 17.2R3-S3."}],"affected":[{"vendor":"Juniper Networks","product":"Junos OS","versions":[{"version":"17.2R3-S3","status":"affected"},{"version":"unspecified","status":"unaffected","lessThan":"17.2R3-S3","versionType":"custom"},{"version":"17.3R3-S3","status":"affected","lessThan":"17.3*","changes":[{"at":"17.3R3-S8","status":"unaffected"}],"versionType":"custom"},{"version":"17.4R2-S4, 17.4R3","status":"affected","lessThan":"17.4*","changes":[{"at":"17.4R2-S10, 17.4R3-S2","status":"unaffected"}],"versionType":"custom"},{"version":"18.1R3-S6","status":"affected","lessThan":"18.1*","changes":[{"at":"18.1R3-S10","status":"unaffected"}],"versionType":"custom"},{"version":"18.2R3","status":"affected","lessThan":"18.2*","changes":[{"at":"18.2R3-S4","status":"unaffected"}],"versionType":"custom"},{"version":"18.2X75-D50, 18.2X75-D60","status":"affected","lessThan":"18.2X75*","changes":[{"at":"18.2X75-D53, 18.2X75-D65","status":"unaffected"}],"versionType":"custom"},{"version":"18.3R2","status":"affected","lessThan":"18.3*","changes":[{"at":"18.3R2-S4, 18.3R3-S2","status":"unaffected"}],"versionType":"custom"},{"version":"18.4R2","status":"affected","lessThan":"18.4*","changes":[{"at":"18.4R2-S5, 18.4R3-S2","status":"unaffected"}],"versionType":"custom"},{"version":"19.1R1","status":"affected","lessThan":"19.1*","changes":[{"at":"19.1R2-S2, 19.1R3-S1","status":"unaffected"}],"versionType":"custom"},{"version":"19.2R1","status":"affected","lessThan":"19.2*","changes":[{"at":"19.2R1-S5, 19.2R2","status":"unaffected"}],"versionType":"custom"},{"version":"19.3","status":"affected","lessThan":"19.3R2-S3, 19.3R3","versionType":"custom"},{"version":"19.4","status":"affected","lessThan":"19.4R1-S3, 19.4R2","versionType":"custom"},{"version":"20.1","status":"affected","lessThan":"20.1R1-S2, 20.1R2","versionType":"custom"}]},{"vendor":"Juniper Networks","product":"Junos OS Evolved","versions":[{"version":"19.4-EVO","status":"affected"},{"version":"20.1-EVO","status":"affected","lessThan":"20.1R2-EVO","versionType":"custom"}]}],"references":[{"url":"https://kb.juniper.net/JSA11059","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-20","description":"CWE-20 Improper Input Validation","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"juniper","dateUpdated":"2020-10-16T20:31:26.000Z","orgId":"8cbe9d5a-a066-4c94-8978-4b15efeae968"},"configurations":[{"lang":"en","value":"The example of the configuration stanza affected by this issue is as follows:\n  [protocols bgp damping]\n\nused in combination with accepted-prefix-limit configuration:\n  [protocols bgp   ... accepted-prefix-limit]"}],"datePublic":"2020-10-14T00:00:00.000Z","exploits":[{"lang":"en","value":"Juniper SIRT is not aware of any malicious exploitation of this vulnerability."}],"solutions":[{"lang":"en","value":"The following software releases have been updated to resolve this specific issue:\n\nJunos OS:  17.2R3-S4, 17.3R3-S8, 17.3R3-S9, 17.4R2-S10, 17.4R3-S2, 18.1R3-S10, 18.2R3-S4, 18.2X75-D53, 18.2X75-D65, 18.3R2-S4, 18.3R3-S2, 18.4R2-S5, 18.4R3-S2, 19.1R2-S2, 19.1R3-S1, 19.2R1-S5, 19.2R2, 19.3R2-S3, 19.3R3, 19.4R1-S3, 19.4R2, 20.1R1-S2, 20.1R2, 20.2R1, and all subsequent releases.\n\n\nJunos OS Evolved: 20.1R2-EVO, and all subsequent releases."}],"source":{"advisory":"JSA11059","defect":["1490079"],"discovery":"USER"},"workarounds":[{"lang":"en","value":"There are multiple workarounds that can be applied to prevent this issue:\n\n1.  Disable BGP router flap damping.\n\n2.  Replace \"accepted-prefix-limit\" with \"prefix-limit\" in the BGP configuration, for example: \n  [edit protocols bgp group ${GRP} neighbor ${NEI} family ${AFI} unicast] \n  +          prefix-limit {\n  -         accepted-prefix-limit {\n\n 3.  Make sure that the BGP session idle-timeout is longer than damping max-suppress time. \nIn other words, by the time a peer is eligible to establish BGP session again, no previously advertised prefixes remain suppressed.\nThe BGP session idle time out is configured under:\n  [protocols bgp damping ... teardown <TEARDOWN_VALUE> idle-timeout <IDLE_TIMEOUT_VALUE>]\nThe BGP damping max-suppress time configured under:\n  [protocol bgp damping... max-suppress  <MAX_SUPPRES_VALUE>]\nThe <IDLE_TIMEOUT_VALUE> needs to be higher than <MAX_SUPPRES_VALUE>"}],"x_generator":{"engine":"Vulnogram 0.0.9"},"x_legacyV4Record":{"CVE_data_meta":{"ASSIGNER":"sirt@juniper.net","DATE_PUBLIC":"2020-10-14T16:00:00.000Z","ID":"CVE-2020-1662","STATE":"PUBLIC","TITLE":"Junos OS and Junos OS Evolved: RPD crash due to BGP session flapping."},"affects":{"vendor":{"vendor_data":[{"product":{"product_data":[{"product_name":"Junos OS","version":{"version_data":[{"version_affected":"=","version_name":"17.2","version_value":"17.2R3-S3"},{"version_affected":">=","version_name":"17.3","version_value":"17.3R3-S3"},{"version_affected":"<","version_name":"17.3","version_value":"17.3R3-S8"},{"version_affected":">=","version_name":"17.4","version_value":"17.4R2-S4, 17.4R3"},{"version_affected":"<","version_name":"17.4","version_value":"17.4R2-S10, 17.4R3-S2"},{"version_affected":">=","version_name":"18.1","version_value":"18.1R3-S6"},{"version_affected":"<","version_name":"18.1","version_value":"18.1R3-S10"},{"version_affected":">=","version_name":"18.2","version_value":"18.2R3"},{"version_affected":"<","version_name":"18.2","version_value":"18.2R3-S4"},{"version_affected":">=","version_name":"18.2X75","version_value":"18.2X75-D50, 18.2X75-D60"},{"version_affected":"<","version_name":"18.2X75","version_value":"18.2X75-D53, 18.2X75-D65"},{"version_affected":">=","version_name":"18.3","version_value":"18.3R2"},{"version_affected":"<","version_name":"18.3","version_value":"18.3R2-S4, 18.3R3-S2"},{"version_affected":">=","version_name":"18.4","version_value":"18.4R2"},{"version_affected":"<","version_name":"18.4","version_value":"18.4R2-S5, 18.4R3-S2"},{"version_affected":">=","version_name":"19.1","version_value":"19.1R1"},{"version_affected":"<","version_name":"19.1","version_value":"19.1R2-S2, 19.1R3-S1"},{"version_affected":">=","version_name":"19.2","version_value":"19.2R1"},{"version_affected":"<","version_name":"19.2","version_value":"19.2R1-S5, 19.2R2"},{"version_affected":"<","version_name":"19.3","version_value":"19.3R2-S3, 19.3R3"},{"version_affected":"<","version_name":"19.4","version_value":"19.4R1-S3, 19.4R2"},{"version_affected":"<","version_name":"20.1","version_value":"20.1R1-S2, 20.1R2"},{"version_affected":"!<","version_value":"17.2R3-S3"}]}},{"product_name":"Junos OS Evolved","version":{"version_data":[{"version_affected":"=","version_name":"19.4-EVO","version_value":"19.4-EVO"},{"version_affected":"<","version_name":"20.1-EVO","version_value":"20.1R2-EVO"}]}}]},"vendor_name":"Juniper Networks"}]}},"configuration":[{"lang":"en","value":"The example of the configuration stanza affected by this issue is as follows:\n  [protocols bgp damping]\n\nused in combination with accepted-prefix-limit configuration:\n  [protocols bgp   ... accepted-prefix-limit]"}],"data_format":"MITRE","data_type":"CVE","data_version":"4.0","description":{"description_data":[{"lang":"eng","value":"On Juniper Networks Junos OS and Junos OS Evolved devices, BGP session flapping can lead to a routing process daemon (RPD) crash and restart, limiting the attack surface to configured BGP peers. This issue only affects devices with BGP damping in combination with accepted-prefix-limit configuration. When the issue occurs the following messages will appear in the /var/log/messages: rpd[6046]: %DAEMON-4-BGP_PREFIX_THRESH_EXCEEDED: XXXX (External AS x): Configured maximum accepted prefix-limit threshold(1800) exceeded for inet6-unicast nlri: 1984 (instance master) rpd[6046]: %DAEMON-3-BGP_CEASE_PREFIX_LIMIT_EXCEEDED: 2001:x:x:x::2 (External AS x): Shutting down peer due to exceeding configured maximum accepted prefix-limit(2000) for inet6-unicast nlri: 2001 (instance master) rpd[6046]: %DAEMON-4: bgp_rt_maxprefixes_check_common:9284: NOTIFICATION sent to 2001:x:x:x::2 (External AS x): code 6 (Cease) subcode 1 (Maximum Number of Prefixes Reached) AFI: 2 SAFI: 1 prefix limit 2000 kernel: %KERN-5: mastership_relinquish_on_process_exit: RPD crashed on master RE. Sending SIGUSR2 to chassisd (5612:chassisd) to trigger RE switchover This issue affects: Juniper Networks Junos OS: 17.2R3-S3; 17.3 version 17.3R3-S3 and later versions, prior to 17.3R3-S8; 17.4 version 17.4R2-S4, 17.4R3 and later versions, prior to 17.4R2-S10, 17.4R3-S2; 18.1 version 18.1R3-S6 and later versions, prior to 18.1R3-S10; 18.2 version 18.2R3 and later versions, prior to 18.2R3-S4; 18.2X75 version 18.2X75-D50, 18.2X75-D60 and later versions, prior to 18.2X75-D53, 18.2X75-D65; 18.3 version 18.3R2 and later versions, prior to 18.3R2-S4, 18.3R3-S2; 18.4 version 18.4R2 and later versions, prior to 18.4R2-S5, 18.4R3-S2; 19.1 version 19.1R1 and later versions, prior to 19.1R2-S2, 19.1R3-S1; 19.2 version 19.2R1 and later versions, prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2; 20.1 versions prior to 20.1R1-S2, 20.1R2. Juniper Networks Junos OS Evolved prior to 20.1R2-EVO. This issue does not affect Juniper Networks Junos OS versions prior to 17.2R3-S3."}]},"exploit":[{"lang":"en","value":"Juniper SIRT is not aware of any malicious exploitation of this vulnerability."}],"generator":{"engine":"Vulnogram 0.0.9"},"impact":{"cvss":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"CWE-20 Improper Input Validation"}]}]},"references":{"reference_data":[{"name":"https://kb.juniper.net/JSA11059","refsource":"CONFIRM","url":"https://kb.juniper.net/JSA11059"}]},"solution":[{"lang":"en","value":"The following software releases have been updated to resolve this specific issue:\n\nJunos OS:  17.2R3-S4, 17.3R3-S8, 17.3R3-S9, 17.4R2-S10, 17.4R3-S2, 18.1R3-S10, 18.2R3-S4, 18.2X75-D53, 18.2X75-D65, 18.3R2-S4, 18.3R3-S2, 18.4R2-S5, 18.4R3-S2, 19.1R2-S2, 19.1R3-S1, 19.2R1-S5, 19.2R2, 19.3R2-S3, 19.3R3, 19.4R1-S3, 19.4R2, 20.1R1-S2, 20.1R2, 20.2R1, and all subsequent releases.\n\n\nJunos OS Evolved: 20.1R2-EVO, and all subsequent releases."}],"source":{"advisory":"JSA11059","defect":["1490079"],"discovery":"USER"},"work_around":[{"lang":"en","value":"There are multiple workarounds that can be applied to prevent this issue:\n\n1.  Disable BGP router flap damping.\n\n2.  Replace \"accepted-prefix-limit\" with \"prefix-limit\" in the BGP configuration, for example: \n  [edit protocols bgp group ${GRP} neighbor ${NEI} family ${AFI} unicast] \n  +          prefix-limit {\n  -         accepted-prefix-limit {\n\n 3.  Make sure that the BGP session idle-timeout is longer than damping max-suppress time. \nIn other words, by the time a peer is eligible to establish BGP session again, no previously advertised prefixes remain suppressed.\nThe BGP session idle time out is configured under:\n  [protocols bgp damping ... teardown <TEARDOWN_VALUE> idle-timeout <IDLE_TIMEOUT_VALUE>]\nThe BGP damping max-suppress time configured under:\n  [protocol bgp damping... max-suppress  <MAX_SUPPRES_VALUE>]\nThe <IDLE_TIMEOUT_VALUE> needs to be higher than <MAX_SUPPRES_VALUE>"}]}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://kb.juniper.net/JSA11059","tags":["x_refsource_CONFIRM","x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-04T06:46:29.665Z"}}]}}}