CVE-2020-1679

Junos OS: PTX/QFX Series: Kernel Routing Table (KRT) queue stuck after packet sampling a malformed packet when the tunnel-observation mpls-over-udp configuration is enabled.

HIGH

7.5

CVSS Score

Published: October 16, 2020 at 08:31 PM UTC

Updated: June 17, 2026 at 03:02 AM UTC

20 products affected across 2 vendorsJunosQfx5200Qfx5110

Using Junos OS by Juniper Networks?

Get instant alerts when new vulnerabilities affect Junos OS - before attackers find them.

Real-time alertsTrack your software stackFree plan available

Start Free Sign In

Severity

HIGH7.5

Exploit prediction

EPSS 1%

Description

On Juniper Networks PTX and QFX Series devices with packet sampling configured using tunnel-observation mpls-over-udp, sampling of a malformed packet can cause the Kernel Routing Table (KRT) queue to become stuck. KRT is the module within the Routing Process Daemon (RPD) that synchronized the routing tables with the forwarding tables in the kernel. This table is then synchronized to the Packet Forwarding Engine (PFE) via the KRT queue. Thus, when KRT queue become stuck, it can lead to unexpected packet forwarding issues. An administrator can monitor the following command to check if there is the KRT queue is stuck: user@device > show krt state ... Number of async queue entries: 65007 <--- this value keep on increasing. When this issue occurs, the following message might appear in the /var/log/messages: DATE DEVICE kernel: %KERN-3: rt_pfe_veto: Too many delayed route/nexthop unrefs. Op 2 err 55, rtsm_id 5:-1, msg type 2 DATE DEVICE kernel: %KERN-3: rt_pfe_veto: Memory usage of M_RTNEXTHOP type = (0) Max size possible for M_RTNEXTHOP type = (7297134592) Current delayed unref = (60000), Current unique delayed unref = (18420), Max delayed unref on this platform = (40000) Current delayed weight unref = (60000) Max delayed weight unref on this platform= (400000) curproc = rpd This issue affects Juniper Networks Junos OS on PTX/QFX Series: 17.2X75 versions prior to 17.2X75-D105; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S5; 18.2X75 versions prior to 18.2X75-D420, 18.2X75-D53, 18.2X75-D65; 18.3 versions prior to 18.3R2-S4, 18.3R3-S3; 18.4 versions prior to 18.4R1-S7, 18.4R2-S5, 18.4R3-S4; 19.1 versions prior to 19.1R2-S2, 19.1R3-S2; 19.2 versions prior to 19.2R1-S5, 19.2R3; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S2, 19.4R2-S1, 19.4R3; 20.1 versions prior to 20.1R1-S2, 20.1R2. This issue does not affect Juniper Networks Junos OS prior to 18.1R1.

Affected

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

Junos · Juniper Networks

95%

17.2X75 ≤ v < 17.2X75-D10518.1 ≤ v < 18.1R3-S1118.2 ≤ v < 18.2R3-S518.2X75 ≤ v < 18.2X75-D420, 18.2X75-D53, 18.2X75-D6518.3 ≤ v < 18.3R2-S4, 18.3R3-S318.4 ≤ v < 18.4R1-S7, 18.4R2-S5, 18.4R3-S419.1 ≤ v < 19.1R2-S2, 19.1R3-S219.2 ≤ v < 19.2R1-S5, 19.2R319.3 ≤ v < 19.3R2-S3, 19.3R319.4 ≤ v < 19.4R1-S2, 19.4R2-S1, 19.4R320.1 ≤ v < 20.1R1-S2, 20.1R217.2X7517.2x7517.2x75 d102 17.2x75 d50 17.2x75 d70 17.2x75 d92 18.1 18.1 r1 18.1 r2 18.1 r2-s1 18.1 r2-s2 18.1 r2-s4 18.1 r3 18.1 r3-s1 18.1 r3-s10 18.1 r3-s2 18.1 r3-s3 18.1 r3-s4 18.1 r3-s6 18.1 r3-s7 18.1 r3-s8 18.1 r3-s9 18.2 18.2 r1 18.2 r1-s3 18.2 r1-s4 18.2 r1-s5 18.2 r2 18.2 r2-s1 18.2 r2-s2 18.2 r2-s3 18.2 r2-s4 18.2 r2-s5 18.2 r2-s6 18.2 r3 18.2 r3-s1 18.2 r3-s2 18.2 r3-s3 18.2 r3-s4 18.2X7518.2x7518.2x75 d1218.2x75 d20 18.2x75 d30 18.2x75 d4018.2x75 d41118.2x75 d5118.3 18.3 r1 18.3 r1-s1 18.3 r1-s2 18.3 r1-s3 18.3 r1-s5 18.3 r1-s6 18.3 r2 18.3 r2-s1 18.3 r2-s2 18.3 r2-s3 18.3 r3 18.3 r3-s1 18.3 r3-s2 18.4 18.4 r1 18.4 r1-s1 18.4 r1-s2 18.4 r1-s5 18.4 r1-s6 18.4 r2 18.4 r2-s1 18.4 r2-s2 18.4 r2-s3 18.4 r2-s4 18.4 r3 18.4 r3-s1 18.4 r3-s2 18.4 r3-s3 19.1 19.1 r1 19.1 r1-s1 19.1 r1-s2 19.1 r1-s3 19.1 r1-s4 19.1 r2 19.1 r2-s1 19.1 r3 19.1 r3-s1 19.2 19.2 r1 19.2 r1-s1 19.2 r1-s2 19.2 r1-s3 19.2 r1-s4 19.3 19.3 r1 19.3 r1-s1 19.3 r2 19.3 r2-s1 19.3 r2-s2 19.4 19.4 r1 19.4 r1-s1 19.4 r2 20.1 20.1 r1 20.1 r1-s1

Affected range stops below 17.2X75-D105, so it looks safe — our inference, not a vendor statement

Vendor states this is fixed in 18.1R1 (unaffected)

Affected range stops below 18.1R3-S11, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.2R3-S5, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.2X75-D420, 18.2X75-D53, 18.2X75-D65, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.3R2-S4, 18.3R3-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.4R1-S7, 18.4R2-S5, 18.4R3-S4, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.1R2-S2, 19.1R3-S2, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.2R1-S5, 19.2R3, so it looks safe — our inference, not a vendor statement

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

Affected range stops below 19.4R1-S2, 19.4R2-S1, 19.4R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.1R1-S2, 20.1R2, so it looks safe — our inference, not a vendor statement

juniper-ptx1000 (environment) · juniper-ptx10001-36mr (environment) · juniper-ptx100016 (environment) · juniper-ptx10002 (environment) · juniper-ptx10003 (environment) · juniper-ptx10004 (environment) · juniper-ptx10008 (environment) · juniper-ptx3000 (environment) · juniper-ptx5000 (environment) · juniper-qfx10002 (environment) · juniper-qfx10008 (environment) · juniper-qfx10016 (environment) · juniper-qfx5100 (environment) · juniper-qfx5110 (environment) · juniper-qfx5120 (environment) · juniper-qfx5130 (environment) · juniper-qfx5200 (environment) · juniper-qfx5210 (environment) · juniper-qfx5220 (environment)

Ptx1000 · Juniperdevice

80%

All versions

Ptx10001-36Mr · Juniperdevice

80%

All versions

Ptx100016 · Juniperdevice

80%

All versions

Ptx10002 · Juniperdevice

80%

All versions