{"id":"CVE-2026-33780","aliases":["EUVD-2026-21090","GHSA-wcmx-9w9j-q7ph"],"status":"published","title":"Junos OS and Junos OS Evolved: In an EVPN-MPLS scenario churn of ESI routes causes a memory leak in l2ald","description":"A Missing Release of Memory after Effective Lifetime vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause a memory leak ultimately leading to a Denial of Service (DoS).\n\n\n\nIn an EVPN-MPLS scenario, routes learned from remote multi-homed Provider Edge (PE) devices are programmed as ESI routes. Due to a logic issue in the l2ald memory management, memory allocated for these routes is not released when there is churn for these routes. As a result, memory leaks in the l2ald process which will ultimately lead to a crash and restart of l2ald.\n\nUse the following command to monitor the memory consumption by l2ald:\n\nuser@device\u003e show system process extensive | match \"PID|l2ald\" \n\n\n\nThis issue affects:\n\nJunos OS:\n\n\n\n  *  all versions before 22.4R3-S5,\n  *  23.2 versions before 23.2R2-S3,\n  *  23.4 versions before 23.4R2-S4,\n  *  24.2 versions before 24.2R2;\n\n\n\n\nJunos OS Evolved:\n\n\n\n  *  all versions before 22.4R3-S5-EVO,\n  *  23.2 versions before 23.2R2-S3-EVO,\n  *  23.4 versions before 23.4R2-S4-EVO,\n  *  24.2 versions before 24.2R2-EVO.","severity":{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/RE:M","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00181,"percentile":0.07801,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-401"],"published":"2026-04-09T21:29:20Z","modified":"2026-10-26T22:10:00Z","products":[{"vendor":"juniper","product":"junos"},{"vendor":"juniper","product":"junos_os_evolved"},{"vendor":"juniper networks","product":"junos os"},{"vendor":"juniper networks","product":"junos os evolved"}],"references":[{"url":"https://kb.juniper.net/JSA107819","tags":["vendor-advisory","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33780"},{"url":"https://github.com/advisories/GHSA-wcmx-9w9j-q7ph"}],"sources":{"cve":[{"id":"CVE-2026-33780","title":"Junos OS and Junos OS Evolved: In an EVPN-MPLS scenario churn of ESI routes causes a memory leak in l2ald","description":"A Missing Release of Memory after Effective Lifetime vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause a memory leak ultimately leading to a Denial of Service (DoS).\n\n\n\nIn an EVPN-MPLS scenario, routes learned from remote multi-homed Provider Edge (PE) devices are programmed as ESI routes. Due to a logic issue in the l2ald memory management, memory allocated for these routes is not released when there is churn for these routes. As a result, memory leaks in the l2ald process which will ultimately lead to a crash and restart of l2ald.\n\nUse the following command to monitor the memory consumption by l2ald:\n\nuser@device\u003e show system process extensive | match \"PID|l2ald\" \n\n\n\nThis issue affects:\n\nJunos OS:\n\n\n\n  *  all versions before 22.4R3-S5,\n  *  23.2 versions before 23.2R2-S3,\n  *  23.4 versions before 23.4R2-S4,\n  *  24.2 versions before 24.2R2;\n\n\n\n\nJunos OS Evolved:\n\n\n\n  *  all versions before 22.4R3-S5-EVO,\n  *  23.2 versions before 23.2R2-S3-EVO,\n  *  23.4 versions before 23.4R2-S4-EVO,\n  *  24.2 versions before 24.2R2-EVO.","status":"published","published":"2026-04-09T21:29:20.534Z","modified":"2026-04-13T18:06:19.95Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/RE:M","level":"high","assessor":"cna"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-401"],"updated_at":"2026-11-02T14:20:08.009733Z"}],"euvd":[{"id":"EUVD-2026-21090","description":"A Missing Release of Memory after Effective Lifetime vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause a memory leak ultimately leading to a Denial of Service (DoS).\n\n\n\nIn an EVPN-MPLS scenario, routes learned from remote multi-homed Provider Edge (PE) devices are programmed as ESI routes. Due to a logic issue in the l2ald memory management, memory allocated for these routes is not released when there is churn for these routes. As a result, memory leaks in the l2ald process which will ultimately lead to a crash and restart of l2ald.\n\nUse the following command to monitor the memory consumption by l2ald:\n\nuser@device\u003e show system process extensive | match \"PID|l2ald\" \n\n\n\nThis issue affects:\n\nJunos OS:\n\n\n\n  *  all versions before 22.4R3-S5,\n  *  23.2 versions before 23.2R2-S3,\n  *  23.4 versions before 23.4R2-S4,\n  *  24.2 versions before 24.2R2;\n\n\n\n\nJunos OS Evolved:\n\n\n\n  *  all versions before 22.4R3-S5-EVO,\n  *  23.2 versions before 23.2R2-S3-EVO,\n  *  23.4 versions before 23.4R2-S4-EVO,\n  *  24.2 versions before 24.2R2-EVO.","status":"published","published":"2026-04-09T21:29:20Z","modified":"2026-04-13T18:06:19Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/RE:M","level":"high"}],"updated_at":"2026-11-02T19:24:27.467761Z"}],"ghsa":[{"id":"GHSA-wcmx-9w9j-q7ph","title":"A Missing Release of Memory after Effective Lifetime vulnerability in the Layer 2 Address...","description":"A Missing Release of Memory after Effective Lifetime vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause a memory leak ultimately leading to a Denial of Service (DoS).\n\n\n\nIn an EVPN-MPLS scenario, routes learned from remote multi-homed Provider Edge (PE) devices are programmed as ESI routes. Due to a logic issue in the l2ald memory management, memory allocated for these routes is not released when there is churn for these routes. As a result, memory leaks in the l2ald process which will ultimately lead to a crash and restart of l2ald.\n\nUse the following command to monitor the memory consumption by l2ald:\n\nuser@device\u003e show system process extensive | match \"PID|l2ald\" \n\n\n\nThis issue affects:\n\nJunos OS:\n\n\n\n  *  all versions before 22.4R3-S5,\n  *  23.2 versions before 23.2R2-S3,\n  *  23.4 versions before 23.4R2-S4,\n  *  24.2 versions before 24.2R2;\n\n\n\n\nJunos OS Evolved:\n\n\n\n  *  all versions before 22.4R3-S5-EVO,\n  *  23.2 versions before 23.2R2-S3-EVO,\n  *  23.4 versions before 23.4R2-S4-EVO,\n  *  24.2 versions before 24.2R2-EVO.","status":"published","published":"2026-04-10T00:30:29Z","modified":"2026-04-10T00:30:37Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:M/U:X","level":"high"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-401"],"updated_at":"2026-11-02T15:07:24.354029Z"}],"nvd":[{"id":"CVE-2026-33780","description":"A Missing Release of Memory after Effective Lifetime vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause a memory leak ultimately leading to a Denial of Service (DoS).\n\n\n\nIn an EVPN-MPLS scenario, routes learned from remote multi-homed Provider Edge (PE) devices are programmed as ESI routes. Due to a logic issue in the l2ald memory management, memory allocated for these routes is not released when there is churn for these routes. As a result, memory leaks in the l2ald process which will ultimately lead to a crash and restart of l2ald.\n\nUse the following command to monitor the memory consumption by l2ald:\n\nuser@device\u003e show system process extensive | match \"PID|l2ald\" \n\n\n\nThis issue affects:\n\nJunos OS:\n\n\n\n  *  all versions before 22.4R3-S5,\n  *  23.2 versions before 23.2R2-S3,\n  *  23.4 versions before 23.4R2-S4,\n  *  24.2 versions before 24.2R2;\n\n\n\n\nJunos OS Evolved:\n\n\n\n  *  all versions before 22.4R3-S5-EVO,\n  *  23.2 versions before 23.2R2-S3-EVO,\n  *  23.4 versions before 23.4R2-S4-EVO,\n  *  24.2 versions before 24.2R2-EVO.","status":"published","published":"2026-04-09T22:16:26.96Z","modified":"2026-10-26T22:10:00.163Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:M/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"}],"cwes":["CWE-401"],"updated_at":"2026-11-02T14:12:13.902911Z"}]}}