Junos OS: A race condition on receipt of crafted LLDP packets leads to a memory leak and an LLDP crash.

Description

A Race Condition vulnerability in Juniper Networks Junos OS LLDP implementation allows an attacker to cause LLDP to crash leading to a Denial of Service (DoS). This issue occurs when crafted LLDP packets are received by the device from an adjacent device. Multiple LACP flaps will occur after LLDP crashes. An indicator of compromise is to evaluate log file details for lldp with RLIMIT. Intervention should occur before 85% threshold of used KB versus maximum available KB memory is reached. show log messages | match RLIMIT | match lldp | last 20 Matching statement is " /kernel: %KERNEL-[number]: Process ([pid #],lldpd) has exceeded 85% of RLIMIT_DATA: " with [] as variable data to evaluate for. This issue affects: Juniper Networks Junos OS: 12.3 versions prior to 12.3R12-S15; 12.3X48 versions prior to 12.3X48-D95; 15.1 versions prior to 15.1R7-S6; 15.1X49 versions prior to 15.1X49-D200; 15.1X53 versions prior to 15.1X53-D593; 16.1 versions prior to 16.1R7-S7; 17.1 versions prior to 17.1R2-S11, 17.1R3-S2; 17.2 versions prior to 17.2R1-S9, 17.2R3-S3; 17.3 versions prior to 17.3R2-S5, 17.3R3-S6; 17.4 versions prior to 17.4R2-S4, 17.4R3; 18.1 versions prior to 18.1R3-S5; 18.2 versions prior to 18.2R2-S7, 18.2R3; 18.2X75 versions prior to 18.2X75-D12, 18.2X75-D33, 18.2X75-D50, 18.2X75-D420; 18.3 versions prior to 18.3R1-S7, 18.3R2-S3, 18.3R3; 18.4 versions prior to 18.4R1-S5, 18.4R2; 19.1 versions prior to 19.1R1-S4, 19.1R2.

Scores

EPSS (exploitation in 30 days)

0.40% · top 66% of all CVEs (6 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.

Weakness

• CWE-362 Race Condition (Concurrent Execution using Shared Resource with Improper Synchronization) (opens in a new tab)All about CWE-362 and its CVEs
• Denial of Service (DoS)

Affected products

• Juniper Networks · Junos OS

  • affected 12.3 – < 12.3R12-S15
  • affected 12.3X48 – < 12.3X48-D95
  • affected 15.1 – < 15.1R7-S6
  • affected 15.1X49 – < 15.1X49-D200
  • affected 15.1X53 – < 15.1X53-D593
  • affected 16.1 – < 16.1R7-S7
  • affected 17.1 – < 17.1R2-S11, 17.1R3-S2
  • affected 17.2 – < 17.2R1-S9, 17.2R3-S3
  • affected 17.3 – < 17.3R2-S5, 17.3R3-S6
  • affected 17.4 – < 17.4R2-S4, 17.4R3
  • affected 18.1 – < 18.1R3-S5
  • affected 18.2 – < 18.2R2-S7, 18.2R3
  • affected 18.2X75 – < 18.2X75-D12, 18.2X75-D33, 18.2X75-D50, 18.2X75-D420
  • affected 18.3 – < 18.3R1-S7, 18.3R2-S3, 18.3R3
  • affected 18.4 – < 18.4R1-S5, 18.4R2
  • affected 19.1 – < 19.1R1-S4, 19.1R2

What to do

Solution: The following software releases have been updated to resolve this specific issue: 12.3R12-S15, 12.3X48-D95, 15.1R7-S6, 15.1X49-D200, 15.1X53-D593, 16.1R7-S7, 16.1R7-S7, 17.1R2-S11, 17.1R3-S2, 17.2R1-S9, 17.2R3-S3, 17.3R2-S5, 17.3R3-S6, 17.4R2-S4, 17.4R3, 18.1R3-S5, 18.2R2-S7, 18.2R3, 18.2X75-D33, 18.2X75-D50, 18.2X75-D420, 18.3R1-S7, 18.3R2-S3, 18.3R3, 18.4R1-S5, 18.4R2, 19.1R1-S4, 19.1R2, 19.2R1, and all subsequent releases.

Workaround: Customers may disable LLDP "protocol lldp" or apply firewall filters to block LLDP traffic on ingress interfaces. There are no other known workarounds.

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

References (1)

• https://kb.juniper.net/JSA11027 (opens in a new tab)x_refsource_MISCx_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-2020-1641](https://trackcve.app/badge/CVE-2020-1641.svg)](https://trackcve.app/cve/CVE-2020-1641)

Record last updated 16 Sept 2024, 19:25 UTC.