CVE-2020-12884Network attack vector

Remote denial of service via CoAP parser over-read

Published Jun 18, 2020 · Updated Aug 4, 2024

Out-of-bounds read in Arm Mbed OS 5.15.3 allows remote attackers to cause service interruption via crafted CoAP packets. The sn_coap_parser_options_parse_multiple_options() routine advances packet_data_pptr by option_len without checking the packet boundary, while a separate pointer-range check is based on allocated heap size rather than actual input length. A remotely delivered malformed CoAP message can therefore read beyond the packet buffer and interrupt the service, with no authentication or user interaction required.

CVSS severity9.8
Critical
EPSS probability1.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Arm Mbed OS 5.15.3 allows remote attackers to cause service interruption via crafted CoAP packets. The sn_coap_parser_options_parse_multiple_options() routine advances packet_data_pptr by option_len without checking the packet boundary, while a separate pointer-range check is based on allocated heap size rather than actual input length. A remotely delivered malformed CoAP message can therefore read beyond the packet buffer and interrupt the service, with no authentication or user interaction required.

The record

CVE
CVE-2020-12884
Published
Jun 18, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 18, 2020CVE 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

9.8NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
7.8NISTAV:N/AC:L/Au:N/C:P/I:N/A:P

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-125Out-of-bounds Read
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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