Junos OS: MX Series: PFE crash on MPC7/8/9 upon receipt of large packets requiring fragmentation

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 large packets requiring fragmentation, generating the following error messages: [LOG: Err] MQSS(0): WO: Packet Error - Error Packets 1, Connection 29 [LOG: Err] eachip_hmcif_rx_intr_handler(7259): EA[0:0]: HMCIF Rx: Injected checksum error detected on WO response - Chunk Address 0x0 [LOG: Err] MQSS(0): DRD: RORD1: CMD reorder ID error - Command 11, Reorder ID 1838, QID 0 [LOG: Err] MQSS(0): DRD: UNROLL0: HMC chunk length error in stage 5 - Chunk Address: 0x4321f3 [LOG: Err] MQSS(0): DRD: UNROLL0: HMC chunk address error in stage 5 - Chunk Address: 0x0 [LOG: Notice] Error: /fpc/8/pfe/0/cm/0/MQSS(0)/0/MQSS_CMERROR_DRD_RORD_ENG_INT_REG_CMD_FSM_STATE_ERR (0x2203cc), scope: pfe, category: functional, severity: major, module: MQSS(0), type: DRD_RORD_ENG_INT: CMD FSM State Error [LOG: Notice] Performing action cmalarm for error /fpc/8/pfe/0/cm/0/MQSS(0)/0/MQSS_CMERROR_DRD_RORD_ENG_INT_REG_CMD_FSM_STATE_ERR (0x2203cc) in module: MQSS(0) with scope: pfe category: functional level: major [LOG: Notice] Performing action get-state for error /fpc/8/pfe/0/cm/0/MQSS(0)/0/MQSS_CMERROR_DRD_RORD_ENG_INT_REG_CMD_FSM_STATE_ERR (0x2203cc) in module: MQSS(0) with scope: pfe category: functional level: major [LOG: Notice] Performing action disable-pfe for error /fpc/8/pfe/0/cm/0/MQSS(0)/0/MQSS_CMERROR_DRD_RORD_ENG_INT_REG_CMD_FSM_STATE_ERR (0x2203cc) in module: MQSS(0) 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-S10, 17.4R3-S2 on MX Series; 18.1 versions prior to 18.1R3-S10 on MX Series; 18.2 versions prior to 18.2R3-S3 on MX Series; 18.2X75 versions prior to 18.2X75-D41, 18.2X75-D430, 18.2X75-D65 on MX Series; 18.3 versions prior to 18.3R1-S7, 18.3R2-S4, 18.3R3-S1 on MX Series; 18.4 versions prior to 18.4R1-S7, 18.4R2-S4, 18.4R3 on MX Series; 19.1 versions prior to 19.1R1-S5, 19.1R2-S1, 19.1R3 on MX Series; 19.2 versions prior to 19.2R1-S4, 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.

Scores

EPSS (exploitation in 30 days)

1.0% · top 36% of all CVEs (7 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.

Weakness

• Denial of Service

Affected products

• Juniper Networks · Junos OS

  • unaffected unspecified – < 17.2
  • affected 17.2 – < 17.2R3-S4
  • affected 17.3 – < 17.3R3-S8
  • affected 17.4 – < 17.4R2-S10, 17.4R3-S2
  • affected 18.1 – < 18.1R3-S10
  • affected 18.2 – < 18.2R3-S3
  • affected 18.2X75 – < 18.2X75-D41, 18.2X75-D430, 18.2X75-D65
  • affected 18.3 – < 18.3R1-S7, 18.3R2-S4, 18.3R3-S1
  • affected 18.4 – < 18.4R1-S7, 18.4R2-S4, 18.4R3
  • affected 19.1 – < 19.1R1-S5, 19.1R2-S1, 19.1R3
  • affected 19.2 – < 19.2R1-S4, 19.2R2
  • affected 19.3 – < 19.3R2-S2, 19.3R3

What to do

Solution: The following software releases have been updated to resolve this specific issue: Junos OS 17.2R3-S4, 17.3R3-S8, 17.4R2-S10, 17.4R3-S2, 18.1R3-S10, 18.2R3-S3, 18.2X75-D41, 18.2X75-D430, 18.2X75-D65, 18.3R1-S7, 18.3R2-S4, 18.3R3-S1, 18.4R1-S7, 18.4R2-S4, 18.4R3, 19.1R1-S5, 19.1R2-S1, 19.1R3, 19.2R1-S4, 19.2R2, 19.3R2-S2, 19.3R3, 19.4R1, 19.4R2, 20.1R1, and all subsequent releases.

Workaround: There are no available workarounds for this issue.

Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

References (2)

• https://www.juniper.net/documentation/en_US/junos/topics/topic-map/l2tp-lns-inline-service-interfaces.html (opens in a new tab)x_refsource_MISCx_transferred
• https://kb.juniper.net/JSA11041 (opens in a new tab)x_refsource_CONFIRMx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2020-1655](https://trackcve.app/badge/CVE-2020-1655.svg)](https://trackcve.app/cve/CVE-2020-1655)

Record last updated 16 Sept 2024, 17:38 UTC.