CVE-2021-31367

Junos OS: PTX Series: An FPC heap memory leak will be triggered by certain Flowspec route operations which can lead to an FPC crash

MEDIUM

6.5

CVSS Score

Published: October 19, 2021 at 06:16 PM UTC

Updated: June 17, 2026 at 03:51 AM UTC

10 products affected across 2 vendorsJunosPtx10008Ptx10003

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Severity

MEDIUM6.5

Exploit prediction

EPSS 0.4%

Description

A Missing Release of Memory after Effective Lifetime vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on PTX Series allows an adjacent attacker to cause a Denial of Service (DoS) by sending genuine BGP flowspec packets which cause an FPC heap memory leak. Once having run out of memory the FPC will crash and restart along with a core dump. Continued receipted of these packets will create a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS All versions prior to 18.4R3-S9; 19.1 versions prior to 19.1R3-S7; 19.2 versions prior to 19.2R1-S7, 19.2R3-S3; 19.3 versions prior to 19.3R2-S6, 19.3R3-S3; 19.4 versions prior to 19.4R1-S4, 19.4R3-S6; 20.1 versions prior to 20.1R2-S2, 20.1R3; 20.2 versions prior to 20.2R3-S1; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2. Juniper Networks Junos Evolved is not affected.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Junos · Juniper Networks

95%

v < 18.4R3-S919.1 ≤ v < 19.1R3-S719.2 ≤ v < 19.2R1-S7, 19.2R3-S319.3 ≤ v < 19.3R2-S6, 19.3R3-S319.4 ≤ v < 19.4R1-S4, 19.4R3-S620.1 ≤ v < 20.1R2-S2, 20.1R320.2 ≤ v < 20.2R3-S120.3 ≤ v < 20.3R320.4 ≤ v < 20.4R321.1 ≤ v < 21.1R218.4 18.4 r1 18.4 r1-s1 18.4 r1-s2 18.4 r1-s3 18.4 r1-s4 18.4 r1-s5 18.4 r1-s6 18.4 r1-s7 18.4 r2 18.4 r2-s1 18.4 r2-s2 18.4 r2-s3 18.4 r2-s4 18.4 r2-s5 18.4 r2-s6 18.4 r2-s7 18.4 r2-s8 18.4 r3 18.4 r3-s1 18.4 r3-s2 18.4 r3-s3 18.4 r3-s4 18.4 r3-s5 18.4 r3-s6 18.4 r3-s7 18.4 r3-s8 19.1 19.1 r1 19.1 r1-s1 19.1 r1-s2 19.1 r1-s3 19.1 r1-s4 19.1 r1-s5 19.1 r1-s6 19.1 r2 19.1 r2-s1 19.1 r2-s2 19.1 r3 19.1 r3-s1 19.1 r3-s2 19.1 r3-s3 19.1 r3-s4 19.1 r3-s5 19.1 r3-s6 19.2 19.2 r1 19.2 r1-s1 19.2 r1-s2 19.2 r1-s3 19.2 r1-s4 19.2 r1-s5 19.2 r1-s6 19.2 r2 19.2 r2-s1 19.2 r3 19.2 r3-s1 19.2 r3-s2 19.3 19.3 r1 19.3 r1-s1 19.3 r2 19.3 r2-s1 19.3 r2-s2 19.3 r2-s3 19.3 r2-s4 19.3 r2-s5 19.3 r3 19.3 r3-s1 19.3 r3-s2 19.4 19.4 r1 19.4 r1-s1 19.4 r1-s2 19.4 r1-s3 19.4 r3 19.4 r3-s1 19.4 r3-s2 19.4 r3-s3 19.4 r3-s4 19.4 r3-s5 20.1 20.1 r1 20.1 r1-s1 20.1 r1-s2 20.1 r1-s3 20.1 r1-s4 20.1 r2 20.1 r2-s1 20.2 20.2 r1 20.2 r1-s1 20.2 r1-s2 20.2 r1-s3 20.2 r2 20.2 r2-s1 20.2 r2-s2 20.2 r2-s3 20.2 r3 20.3 20.3 r1 20.3 r1-s1 20.3 r2 20.3 r2-s1 20.4 20.4 r1 20.4 r1-s1 20.4 r2 20.4 r2-s1 21.1 21.1 r1 21.1 r1-s1

Affected range stops below 18.4R3-S9, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.1R3-S7, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.2R1-S7, 19.2R3-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.3R2-S6, 19.3R3-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.4R1-S4, 19.4R3-S6, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.1R2-S2, 20.1R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.2R3-S1, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.3R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.4R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.1R2, so it looks safe — our inference, not a vendor statement

juniper-ptx1000 (environment) · juniper-ptx10001-36mr (environment) · juniper-ptx10002 (environment) · juniper-ptx10003 (environment) · juniper-ptx10004 (environment) · juniper-ptx10008 (environment) · juniper-ptx10016 (environment) · juniper-ptx3000 (environment) · juniper-ptx5000 (environment)

Ptx1000 · Juniperdevice

80%

All versions

Ptx10001-36Mr · Juniperdevice

80%

All versions

Ptx10002 · Juniperdevice

80%

All versions

Ptx10003 · Juniperdevice

80%

All versions