CVE-2026-33780

#!/usr/bin/env python3 # PoC simulation for CVE-2026-33780 # This script simulates the monitoring of the memory leak # Triggering the actual leak requires a specific EVPN-MPLS environment. import time def check_memory_leak(): """ Simulate checking the memory usage as suggested in the advisory. Command: show system process extensive | match "PID|l2ald" """ print("[*] Monitoring l2ald process memory...") # In a real exploit, we would observe increasing memory usage here for i in range(5): print(f"[*] Check cycle {i+1}: Memory usage increasing...") time.sleep(1) print("[!] Potential DoS condition detected if memory does not free up.") def simulate_route_churn(): """ Simulate the trigger: Route churn in EVPN-MPLS. An adjacent attacker would send route updates to cause memory allocation without release. """ print("[*] Simulating EVPN route churn...") # Logic to send BGP updates would go here print("[+] Trigger sent. l2ald should allocate memory and fail to release it.") if __name__ == "__main__": simulate_route_churn() check_memory_leak()

{"cve": {"id": "CVE-2026-33780", "sourceIdentifier": "[email protected]", "published": "2026-04-09T22:16:26.960", "lastModified": "2026-04-17T17:59:50.417", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "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> 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."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "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", "baseScore": 7.1, "baseSeverity": "HIGH", "attackVector": "ADJACENT", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "LOW", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "YES", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "MODERATE", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "ADJACENT_NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-401"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*", "versionEndExcluding": "22.4", "matchCriteriaId": "57F66641-003B-49D6-A9B9-AB300CFE3C93"}, {"vulnerable": true, "criteria": "cpe:2.3:o:juniper:junos:22.4:-:*:*:*:*:*:*", "matchCriteriaId": "1379EF30-AF04-4F98-8328-52A631F24737"}, {"vulnerable": true, "criteria": "cpe:2.3:o:juniper:junos:22.4:r1:*:*:*:*:*:*", "matchCriteriaId": "28E42A41-7965-456B-B0AF-9D3229CE4D4C"}, {"vulnerable": true, "criteria": "cpe:2.3:o:juniper:junos:22.4:r1-s1:*:*:*:*:*:*", "matchCriteriaId": "CB1A77D6-D3AD-481B-979C-8F778530B175"}, {"vulnerable": true, "criteria": "cpe:2.3:o:juniper:junos:22.4:r1-s2:*:*:*:*:*:*", "matchCriteriaId": "3A064B6B-A99B-4D8D-A62D-B00C7870BC30"}, {"vulnerable": true, "criteria": "cpe:2.3:o:juniper:junos:22.4:r2:*:*:*:*:*:*", "matchCriteriaId": "40813417-A938-4F74-A419-8C5188A35486"}, {"vulnerable": true, "criteria": "cpe:2.3:o:juniper:junos:22.4:r2-s1:*:*:*:*:*:*", "matchCriteriaId": "7FC1BA1A-DF0E-4B15-86BA-24C60E546732"}, {"vulnerable": true, "criteria": "cpe:2.3:o:juniper:junos:22.4:r2-s2:*:*:*:*:*:*", "matchCriteriaId": "EBB967BF-3495-476D-839A-9DBFCBE69F91"}, {"vulnerable": true, "criteria": "cpe:2.3:o:juniper:junos:22.4:r3:*:*:*:*:*:*", "matchCriteriaId": "7E5688D6-DCA4-4550-9CD1-A3D792252129"}, {"vulnerable": true, "criteria": "cpe ... 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