CVE-2023-23305Public exploitNetwork attack vector

Firmware execution hijack via font size overflow

Published May 23, 2023 · Updated Jan 31, 2025

Buffer overflows in GarminOS TVM in CIQ API 1.0.0 through 4.1.7 allow attackers to hijack device firmware via a malicious application. _tvm_app_load_resource trusts font header glyph counts and data sizes, allowing 32-bit allocation arithmetic to wrap before glyph data is copied out of bounds. The malicious CIQ application must embed and load a crafted font resource; the published proof of concept demonstrates a firmware crash, while the advisory reports firmware execution control.

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

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Buffer overflows in GarminOS TVM in CIQ API 1.0.0 through 4.1.7 allow attackers to hijack device firmware via a malicious application. _tvm_app_load_resource trusts font header glyph counts and data sizes, allowing 32-bit allocation arithmetic to wrap before glyph data is copied out of bounds. The malicious CIQ application must embed and load a crafted font resource; the published proof of concept demonstrates a firmware crash, while the advisory reports firmware execution control.

The record

CVE
CVE-2023-23305
Published
May 23, 2023
Updated
Jan 31, 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 31, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

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

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NVDCVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo