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No exploitation reported

CVE-2020-1653

No exploitation reported by the sources we read.

  • Published2020-07-17
  • WeaknessCWE-159 · CWE-772

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

On Juniper Networks Junos OS devices, a stream of TCP packets sent to the Routing Engine (RE) may cause mbuf leak which can lead to Flexible PIC Concentrator (FPC) crash or the system to crash and restart (vmcore). This issue can be trigged by IPv4 or IPv6 and it is caused only by TCP packets. This issue is not related to any specific configuration and it affects Junos OS releases starting from 17.4R1. However, this issue does not affect Junos OS releases prior to 18.2R1 when Nonstop active routing (NSR) is configured [edit routing-options nonstop-routing]. The number of mbufs is platform dependent. The following command provides the number of mbufs counter that are currently in use and maximum number of mbufs that can be allocated on a platform: user@host> show system buffers 2437/3143/5580 mbufs in use (current/cache/total) Once the device runs out of mbufs, the FPC crashes or the vmcore occurs and the device might become inaccessible requiring a manual restart. This issue affects Juniper Networks Junos OS 17.4 versions prior to 17.4R2-S11, 17.4R3-S2; 18.1 versions prior to 18.1R3-S10; 18.2 versions prior to 18.2R2-S7, 18.2R3-S5; 18.2X75 versions prior to 18.2X75-D41, 18.2X75-D420.12, 18.2X75-D51, 18.2X75-D60, 18.2X75-D34; 18.3 versions prior to 18.3R2-S4, 18.3R3-S2; 18.4 versions prior to 18.4R1-S7, 18.4R2-S4, 18.4R3-S1; 19.1 versions prior to 19.1R1-S5, 19.1R2-S1, 19.1R3; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S2, 19.4R2. Versions of Junos OS prior to 17.4R1 are unaffected by this vulnerability.

Timeline

dates in UTC
  1. 2020-07-1719:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-1653?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-1653?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Juniper junos
BranchAffectedFixed in
17.4= 17.4no fix published
18.1= 18.1no fix published
18.2= 18.2no fix published
18.2= 18.2x75no fix published
18.3= 18.3no fix published
18.4= 18.4no fix published
19.1= 19.1no fix published
19.2= 19.2no fix published
19.3= 19.3no fix published
19.4= 19.4no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CNACVSS 3.17.5read 2026-10-23
  • NVDCVSS 3.17.5read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • CNAweakness (CWE)CWE-159read 2026-10-23
  • NVDweakness (CWE)CWE-772read 2026-10-23
  • FIRST EPSSEPSS score1.6 %2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2020-07-17
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-1653?

On Juniper Networks Junos OS devices, a stream of TCP packets sent to the Routing Engine (RE) may cause mbuf leak which can lead to Flexible PIC Concentrator (FPC) crash or the system to crash and restart (vmcore). This issue can be trigged by IPv4 or IPv6 and it is caused only by TCP packets. This issue is not related to any specific configuration and it affects Junos OS releases starting from 17.4R1. However, this issue does not affect Junos OS releases prior to 18.2R1 when Nonstop active routing (NSR) is configured [edit routing-options nonstop-routing]. The number of mbufs is platform dependent. The following command provides the number of mbufs counter that are currently in use and maximum number of mbufs that can be allocated on a platform: user@host> show system buffers 2437/3143/5580 mbufs in use (current/cache/total) Once the device runs out of mbufs, the FPC crashes or the vmcore occurs and the device might become inaccessible requiring a manual restart. This issue affects Juniper Networks Junos OS 17.4 versions prior to 17.4R2-S11, 17.4R3-S2; 18.1 versions prior to 18.1R3-S10; 18.2 versions prior to 18.2R2-S7, 18.2R3-S5; 18.2X75 versions prior to 18.2X75-D41, 18.2X75-D420.12, 18.2X75-D51, 18.2X75-D60, 18.2X75-D34; 18.3 versions prior to 18.3R2-S4, 18.3R3-S2; 18.4 versions prior to 18.4R1-S7, 18.4R2-S4, 18.4R3-S1; 19.1 versions prior to 19.1R1-S5, 19.1R2-S1, 19.1R3; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S2, 19.4R2. Versions of Junos OS prior to 17.4R1 are unaffected by this vulnerability.

Is CVE-2020-1653 actively exploited?

Active exploitation of CVE-2020-1653 has not been confirmed. Its EPSS score was 1.6% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-1653?

CVE-2020-1653 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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