Code execution via unchecked VZT prefix copy
Published Jan 8, 2024 · Updated Nov 4, 2025
Heap out-of-bounds write in GTKWave 3.3.115 allows attackers to execute arbitrary code when a victim opens a crafted VZT file. The vzt_rd_get_facname prefix-copy loop trusts the file-controlled clone count and copies that many bytes into heap buffers sized from the file-controlled longestname field without checking their bounds. Exploitation requires a victim to open the malicious file through the GUI or a VZT conversion tool and executes code in that user's context.
Summary
What happened
Heap out-of-bounds write in GTKWave 3.3.115 allows attackers to execute arbitrary code when a victim opens a crafted VZT file. The vzt_rd_get_facname prefix-copy loop trusts the file-controlled clone count and copies that many bytes into heap buffers sized from the file-controlled longestname field without checking their bounds. Exploitation requires a victim to open the malicious file through the GUI or a VZT conversion tool and executes code in that user's context.
The record
- CVE
- CVE-2023-38648
- Published
- Jan 8, 2024
- Updated
- Nov 4, 2025
- Vendor
- GTKWave
- Product
- GTKWave
- Classifications
- CWE-119, T1203, T1204.002
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 8, 2024CVE publishedPublication date reported by the CVE source.
- 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.
- Affected versionversion=3.3.115
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- Cisco Talos VZT prefix-copy triggerproof of concept · demonstrated
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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