CVE-2021-41040Public exploitNetwork attack vector

Remote denial of service via CoAP over-read

Published Feb 1, 2022 · Updated Aug 4, 2024

Out-of-bounds reads in Eclipse Wakaama 1.0 allow remote attackers to crash LwM2M endpoints with malformed CoAP datagrams. coap_parse_message() begins parsing a CoAP header before confirming that data_len meets the minimum header length and can also overrun its fixed options field when the option number is 40. An unauthenticated network path to a Wakaama endpoint is sufficient; a two-byte UDP datagram crashes the example server and interrupts its service.

CVSS severity7.5
High
EPSS probability1.36%
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 reads in Eclipse Wakaama 1.0 allow remote attackers to crash LwM2M endpoints with malformed CoAP datagrams. coap_parse_message() begins parsing a CoAP header before confirming that data_len meets the minimum header length and can also overrun its fixed options field when the option number is 40. An unauthenticated network path to a Wakaama endpoint is sufficient; a two-byte UDP datagram crashes the example server and interrupts its service.

The record

CVE
CVE-2021-41040
Published
Feb 1, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 1, 2022CVE 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

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

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

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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