{"id":"CVE-2020-1649","url":"https://www.cyber-defence.io/tools/cve/CVE-2020-1649","generatedAt":"2026-10-28T04:16:14.337Z","title":"When a device running Juniper Networks Junos OS with MPC7, MPC8, or MPC9 line cards installed and the system is configured for inline IP reassembly, used by L2TP, MAP-E, GRE, and IPIP, the packet forwarding engine (PFE) will become disabled upon receipt…","description":"When a device running Juniper Networks Junos OS with MPC7, MPC8, or MPC9 line cards installed and the system is configured for inline IP reassembly, used by L2TP, MAP-E, GRE, and IPIP, the packet forwarding engine (PFE) will become disabled upon receipt of small fragments requiring reassembly, generating the following error messages: [LOG: Err] MQSS(2): WO: Packet Error - Error Packets 1, Connection 29 [LOG: Err] eachip_hmcif_rx_intr_handler(7259): EA[2:0]: HMCIF Rx: Injected checksum error detected on WO response - Chunk Address 0x0 [LOG: Err] MQSS(2): DRD: RORD1: CMD reorder ID error - Command 11, Reorder ID 1960, QID 0 [LOG: Err] MQSS(2): DRD: UNROLL0: HMC chunk address error in stage 5 - Chunk Address: 0xc38fb1 [LOG: Notice] Error: /fpc/0/pfe/0/cm/0/MQSS(2)/2/MQSS_CMERROR_DRD_RORD_ENG_INT_REG_CMD_FSM_STATE_ERR (0x2203cc), scope: pfe, category: functional, severity: major, module: MQSS(2), type: DRD_RORD_ENG_INT: CMD FSM State Error [LOG: Notice] Performing action cmalarm for error /fpc/0/pfe/0/cm/0/MQSS(2)/2/MQSS_CMERROR_DRD_RORD_ENG_INT_REG_CMD_FSM_STATE_ERR (0x2203cc) in module: MQSS(2) with scope: pfe category: functional level: major [LOG: Notice] Performing action get-state for error /fpc/0/pfe/0/cm/0/MQSS(2)/2/MQSS_CMERROR_DRD_RORD_ENG_INT_REG_CMD_FSM_STATE_ERR (0x2203cc) in module: MQSS(2) with scope: pfe category: functional level: major [LOG: Notice] Performing action disable-pfe for error /fpc/0/pfe/0/cm/0/MQSS(2)/2/MQSS_CMERROR_DRD_RORD_ENG_INT_REG_CMD_FSM_STATE_ERR (0x2203cc) in module: MQSS(2) with scope: pfe category: functional level: major By continuously sending fragmented packets that cannot be reassembled, an attacker can repeatedly disable the PFE causing a sustained Denial of Service (DoS). This issue affects Juniper Networks Junos OS: 17.2 versions prior to 17.2R3-S4 on MX Series; 17.3 versions prior to 17.3R3-S8 on MX Series; 17.4 versions prior to 17.4R2-S9, 17.4R3-S1 on MX Series; 18.1 versions prior to 18.1R3-S10 on MX Series; 18.2 versions prior to 18.2R2-S6, 18.2R3-S3 on MX Series; 18.2X75 versions prior to 18.2X75-D34, 18.2X75-D41, 18.2X75-D53, 18.2X75-D65, 18.2X75-D430 on MX Series; 18.3 versions prior to 18.3R1-S7, 18.3R2-S4, 18.3R3-S2 on MX Series; 18.4 versions prior to 18.4R1-S6, 18.4R2-S4, 18.4R3 on MX Series; 19.1 versions prior to 19.1R1-S4, 19.1R2-S1, 19.1R3 on MX Series; 19.2 versions prior to 19.2R1-S3, 19.2R2 on MX Series; 19.3 versions prior to 19.3R2-S2, 19.3R3 on MX Series. This issue is specific to inline IP reassembly, introduced in Junos OS 17.2. Versions of Junos OS prior to 17.2 are unaffected by this vulnerability.","published":"2020-07-17T19:15:13.000Z","lastModified":"2026-06-17T03:02:07.000Z","status":"Modified","sourceIdentifier":"sirt@juniper.net","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":[],"affected":["juniper/junos"],"epss":{"score":0.01075,"percentile":0.64801,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (1.07%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://kb.juniper.net/JSA11036","tags":["Vendor Advisory"],"source":"sirt@juniper.net"},{"url":"https://www.juniper.net/documentation/en_US/junos/topics/topic-map/l2tp-lns-inline-service-interfaces.html","tags":["Vendor Advisory"],"source":"sirt@juniper.net"},{"url":"https://kb.juniper.net/JSA11036","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.juniper.net/documentation/en_US/junos/topics/topic-map/l2tp-lns-inline-service-interfaces.html","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2020-1649","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}