CVE-2021-33316Network attack vector

Memory corruption via malformed LLDP ChassisID length

Published May 11, 2022 · Updated Aug 3, 2024

Integer underflow in TRENDnet TI-PG1284i firmware before 2.0.2.S0 allows remote attackers to corrupt memory via a crafted LLDP packet. The LLDP component fails to validate the ChassisID TLV length, underflows it, and passes the negative value to memcpy(). The attack requires LLDP packet reachability; the resulting buffer overflow or invalid memory access can corrupt memory and interrupt service.

CVSS severity9.8
Critical
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in TRENDnet TI-PG1284i firmware before 2.0.2.S0 allows remote attackers to corrupt memory via a crafted LLDP packet. The LLDP component fails to validate the ChassisID TLV length, underflows it, and passes the negative value to memcpy(). The attack requires LLDP packet reachability; the resulting buffer overflow or invalid memory access can corrupt memory and interrupt service.

The record

CVE
CVE-2021-33316
Published
May 11, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-20, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 11, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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-20Improper Input Validation
T1499Endpoint Denial of Service

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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