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Vulnerability · Published Oct 19, 2021 · Assigned by juniper

CVE-2021-31379Junos OS: MX Series: MPC 7/8/9/10/11 cards with MAP-E: PFE halts when an attacker sends malformed IPv4 or IPv6 traffic inside the MAP-E tunnel.

High 7.5

In plain English

A high-severity security flaw in Junos OS from Juniper Networks. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.3% (higher than 71% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)1.3%top 28.7% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

An Incorrect Behavior Order vulnerability in the MAP-E automatic tunneling mechanism of Juniper Networks Junos OS allows an attacker to send certain malformed IPv4 or IPv6 packets to cause a Denial of Service (DoS) to the PFE on the device which is disabled as a result of the processing of these packets. Continued receipt and processing of these malformed IPv4 or IPv6 packets will create a sustained Denial of Service (DoS) condition. This issue only affects MPC 7/8/9/10/11 cards, when MAP-E IP reassembly is enabled on these cards. An indicator of compromise is the output: FPC ["FPC ID" # e.g. "0"] PFE #{PFE ID # e.g. "1"] : Fabric Disabled Example: FPC 0 PFE #1 : Fabric Disabled when using the command: show chassis fabric fpcs An example of a healthy result of the command use would be: user@device-re1> show chassis fabric fpcs Fabric management FPC state: FPC 0 PFE #0 Plane 0: Plane enabled Plane 1: Plane enabled Plane 2: Plane enabled Plane 3: Plane enabled Plane 4: Plane enabled Plane 5: Plane enabled Plane 6: Plane enabled Plane 7: Plane enabled This issue affects: Juniper Networks Junos OS on MX Series with MPC 7/8/9/10/11 cards, when MAP-E IP reassembly is enabled on these cards. 17.2 version 17.2R1 and later versions; 17.3 versions prior to 17.3R3-S9; 17.4 versions prior to 17.4R2-S12, 17.4R3-S3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R2-S6, 18.2R3-S3; 18.3 versions prior to 18.3R2-S4, 18.3R3-S1; 18.4 versions prior to 18.4R1-S8, 18.4R2-S5, 18.4R3; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S5, 19.3R3. This issue does not affect Juniper Networks Junos OS versions prior to 17.2R1.

Affected products (as reported)

VendorProductVersions
Juniper Networks Junos OS 17.2R1 – before 17.2*17.3 – before 17.3R3-S917.4 – before 17.4R2-S12, 17.4R3-S318.1 – before 18.1R3-S1118.2 – before 18.2R2-S6, 18.2R3-S318.3 – before 18.3R2-S4, 18.3R3-S118.4 – before 18.4R1-S8, 18.4R2-S5, 18.4R3

Weakness: CWE-696 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References