CVE-2023-23300Public exploitNetwork attack vector

Firmware code execution via post-copy size validation

Published May 23, 2023 · Updated Jan 21, 2025

Buffer overflow in Garmin Connect IQ API 3.0.0 through 4.1.7 allows attackers to execute arbitrary code in device firmware. The Toybox.Cryptography.Cipher.initialize method copies attacker-sized key and initialization-vector byte arrays with memcpy into fixed stack and heap buffers before checking their lengths. Exploitation requires a crafted Connect IQ application to be installed manually or through the Connect IQ Store, after which native execution can compromise the device.

CVSS severity9.8
Critical
EPSS probability1.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Garmin Connect IQ API 3.0.0 through 4.1.7 allows attackers to execute arbitrary code in device firmware. The Toybox.Cryptography.Cipher.initialize method copies attacker-sized key and initialization-vector byte arrays with memcpy into fixed stack and heap buffers before checking their lengths. Exploitation requires a crafted Connect IQ application to be installed manually or through the Connect IQ Store, after which native execution can compromise the device.

The record

CVE
CVE-2023-23300
Published
May 23, 2023
Updated
Jan 21, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 23, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 21, 2025Record 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

9.8NIST 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 exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1203Exploitation for Client Execution

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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