CVE-2020-22283Network attack vector

Unauthenticated memory disclosure via chained pbuf over-read

Published Jul 22, 2021 · Updated Aug 4, 2024

A buffer over-read in Free Software Foundation lwIP git head allows remote attackers to disclose memory via a crafted ICMPv6 packet. The icmp6_send_response_with_addrs_and_netif() function passes p->tot_len to pbuf_take_at() while copying from only p->payload, so a chained pbuf makes the read exceed the first segment. No authentication or user interaction is required; returned ICMPv6 data exposes adjacent memory without modifying it.

CVSS severity7.5
High
EPSS probability1.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A buffer over-read in Free Software Foundation lwIP git head allows remote attackers to disclose memory via a crafted ICMPv6 packet. The icmp6_send_response_with_addrs_and_netif() function passes p->tot_len to pbuf_take_at() while copying from only p->payload, so a chained pbuf makes the read exceed the first segment. No authentication or user interaction is required; returned ICMPv6 data exposes adjacent memory without modifying it.

The record

CVE
CVE-2020-22283
Published
Jul 22, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1190
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

5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
T1190Exploit Public-Facing Application

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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