CVE-2023-39235

Code execution via unchecked VZT autosort index

Published Jan 8, 2024 · Updated Nov 4, 2025

Out-of-bounds writes in GTKWave 3.3.115 allow context-dependent attackers to execute arbitrary code through a crafted VZT file. The vzt_rd_process_block autosort loop uses attacker-controlled i2 values returned by vzt_rd_next_value_chg_time to index an array sized by num_time_ticks without bounds checks. Execution requires a victim to open the file in the GUI or process it with an affected VZT conversion utility.

CVSS severity7.8
High
EPSS probability0.43%
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 writes in GTKWave 3.3.115 allow context-dependent attackers to execute arbitrary code through a crafted VZT file. The vzt_rd_process_block autosort loop uses attacker-controlled i2 values returned by vzt_rd_next_value_chg_time to index an array sized by num_time_ticks without bounds checks. Execution requires a victim to open the file in the GUI or process it with an affected VZT conversion utility.

The record

CVE
CVE-2023-39235
Published
Jan 8, 2024
Updated
Nov 4, 2025
Vendor
GTKWave
Product
GTKWave
Classifications
CWE-129, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 8, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.3.115

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

GTKWave · GTKWaveversion=3.3.115

Published CVSS scores

7.8Cisco TalosCVSS:3.1/AV:L/AC:L/PR:N/UI:R/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-129Improper Validation of Array Index
T1204.002User Execution: Malicious File
T1203Exploitation for Client Execution

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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