CVE-2020-27827Network attack vector

Service interruption via duplicate LLDP TLV leak

Published Mar 18, 2021 · Updated Dec 3, 2025

Uncontrolled resource consumption in Open vSwitch and lldpd allows remote attackers to exhaust memory with crafted LLDP packets. In the shared LLDP decoder, lldp_decode allocates a buffer for each optional port-description, system-name, or system-description TLV, then overwrites the stored pointer when the same TLV recurs without freeing the earlier allocation. The attack requires LLDP processing on the target interface; Open vSwitch disables that processing by default, and repeated packets can interrupt service.

CVSS severity7.5
High
EPSS probability3.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in Open vSwitch and lldpd allows remote attackers to exhaust memory with crafted LLDP packets. In the shared LLDP decoder, lldp_decode allocates a buffer for each optional port-description, system-name, or system-description TLV, then overwrites the stored pointer when the same TLV recurs without freeing the earlier allocation. The attack requires LLDP processing on the target interface; Open vSwitch disables that processing by default, and repeated packets can interrupt service.

The record

CVE
CVE-2020-27827
Published
Mar 18, 2021
Updated
Dec 3, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Dec 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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