CVE-2023-36861Public exploit

Code execution via unchecked VZT varint index

Published Jan 8, 2024 · Updated Nov 4, 2025

An out-of-bounds write in GTKWave 3.3.115 allows attackers to execute arbitrary code via a crafted VZT waveform file. LZMA_read_varint stores file-supplied bytes in a 16-byte stack buffer until a high termination bit appears, but it never bounds the incrementing index. Execution requires a local user to open the file in the GUI or process it with vzt2vcd or vztminer, after which code runs with that user's privileges.

CVSS severity7.8
High
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An out-of-bounds write in GTKWave 3.3.115 allows attackers to execute arbitrary code via a crafted VZT waveform file. LZMA_read_varint stores file-supplied bytes in a 16-byte stack buffer until a high termination bit appears, but it never bounds the incrementing index. Execution requires a local user to open the file in the GUI or process it with vzt2vcd or vztminer, after which code runs with that user's privileges.

The record

CVE
CVE-2023-36861
Published
Jan 8, 2024
Updated
Nov 4, 2025
Vendor
GTKWave
Product
GTKWave
Classifications
CWE-119, CWE-787, 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 exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-787Out-of-bounds Write
T1204.002Malicious File
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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