CVE-2020-22284Network attack vector

Memory disclosure via chained pbuf over-read

Published Jul 22, 2021 · Updated Aug 4, 2024

Buffer over-read in lwIP 2.1.2 allows remote attackers to access sensitive memory via a crafted 6LoWPAN packet. In zepif_linkoutput(), pbuf_take_at() copies p->tot_len bytes from the first chained pbuf payload even though that buffer contains only p->len bytes. The affected ZEP output path must process a chained packet, after which adjacent memory is included in the UDP broadcast without authentication or user interaction.

CVSS severity7.5
High
EPSS probability1.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer over-read in lwIP 2.1.2 allows remote attackers to access sensitive memory via a crafted 6LoWPAN packet. In zepif_linkoutput(), pbuf_take_at() copies p->tot_len bytes from the first chained pbuf payload even though that buffer contains only p->len bytes. The affected ZEP output path must process a chained packet, after which adjacent memory is included in the UDP broadcast without authentication or user interaction.

The record

CVE
CVE-2020-22284
Published
Jul 22, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 22, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

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-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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