{"id":"CVE-2026-103393","kind":"vulnerability","aliases":["CVE-2026-103393"],"related":[],"title":"Juniper Session Smart Router: VRRP flaw leaks memory or crashes the device","description":"An Out-of-Bounds Read vulnerability in the VRRP implementation in Juniper Networks Session Smart Router allows an L2-adjacent attacker to read stale memory contents or cause a system fault via a specially crafted VRRPv3 advertisement.","summary":"A crafted VRRPv3 advertisement sent from the same Layer 2 network triggers an out-of-bounds read in Juniper's Session Smart Router VRRP code. An attacker can read stale memory contents or make the system fault.","severity":"medium","cvss":4.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","juniper","network","session-smart-router","vrrp"],"not_affected_if":["vrrp-not-configured"],"how_to_check":"- Check the installed Session Smart Router software version against Juniper's advisory: unknown\n- Confirm whether VRRP is enabled on the router's interfaces: unknown","fix":"- Move Session Smart Router to the fixed release named in Juniper's advisory: unknown","status":"open","published_at":"2026-10-28T17:17:22+00:00","first_seen_at":"2026-10-28T17:34:08+00:00","triaged_at":"2026-10-28T17:34:43+00:00","updated_at":"2026-10-28T17:34:43+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-28T17:34:43Z","model":"claude-haiku-5-5","output":{"fix":"- Move Session Smart Router to the fixed release named in Juniper's advisory: unknown","reach":"network","title":"Juniper Session Smart Router: VRRP flaw leaks memory or crashes the device","impact":"medium","summary":"A crafted VRRPv3 advertisement sent from the same Layer 2 network triggers an out-of-bounds read in Juniper's Session Smart Router VRRP code. An attacker can read stale memory contents or make the system fault.","category":"infrastructure","nicknames":[],"who_cares":["juniper","session-smart-router","vrrp","network"],"confidence":0.6,"needs_auth":"no","worst_case":"Attacker reads stale memory or crashes the router","analyst_note":"Find Juniper's advisory and the list of affected and fixed Session Smart Router versions; the sources give only the NVD entry.","how_to_check":"- Check the installed Session Smart Router software version against Juniper's advisory: unknown\n- Confirm whether VRRP is enabled on the router's interfaces: unknown","needs_analyst":true,"not_affected_if":["vrrp-not-configured"],"who_is_affected":"Devices running Juniper Session Smart Router with VRRP enabled on a segment where an attacker can send Layer 2 traffic. Routers without VRRP configured, or on isolated segments with no untrusted hosts, are less exposed. The sources do not name affected versions.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000596,"input_tokens":3313,"output_tokens":529,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-103393':15A,18A '-2026':14A,17A '2':36B 'adjac':86C 'advertis':30B,103C 'allow':82C 'attack':54B,87C 'bound':43B,69C 'caus':94C 'code':52B 'content':59B,92C 'craft':28B,101C 'crash':10A 'cve':13A,16A 'devic':12A 'fault':64B,97C 'flaw':6A 'implement':75C 'infrastructur':19B 'junip':1A,20B,46B,77C 'l2':85C 'l2-adjacent':84C 'layer':35B 'leak':7A 'make':61B 'memori':8A,58B,91C 'network':21B,37B,78C 'out-of-bound':40B,66C 'read':44B,56B,70C,89C 'router':4A,25B,50B,81C 'sent':31B 'session':2A,23B,48B,79C 'session-smart-rout':22B 'smart':3A,24B,49B,80C 'special':100C 'stale':57B,90C 'system':63B,96C 'trigger':38B 'via':98C 'vrrp':5A,26B,51B,74C 'vrrpv3':29B,102C 'vulner':71C","nicknames":[],"mitigations":[],"who_affected":"Devices running Juniper Session Smart Router with VRRP enabled on a segment where an attacker can send Layer 2 traffic. Routers without VRRP configured, or on isolated segments with no untrusted hosts, are less exposed. The sources do not name affected versions.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-28T17:17:22+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","cvss_by":"sirt@juniper.net","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-103393","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-103393","severity":null,"published_at":"2026-10-28T17:17:22+00:00","modified_at":"2026-10-28T17:17:23+00:00","first_seen_at":"2026-10-28T17:34:08+00:00","fetched_at":"2026-10-28T17:34:08+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}