Code execution via unbounded LEB128 varint copy
Published Jan 8, 2024 · Updated Nov 4, 2025
Stack-based buffer overflow in GTKWave 3.3.115 allows attackers to execute arbitrary code after a user opens a crafted FST file. fstReaderVarint32 copies attacker-controlled LEB128 bytes into a five-byte stack buffer until a byte clears its high bit, without enforcing the buffer limit. The gate is user interaction; successful exploitation runs code with the privileges of the GTKWave process and can compromise data or interrupt the process.
Summary
What happened
Stack-based buffer overflow in GTKWave 3.3.115 allows attackers to execute arbitrary code after a user opens a crafted FST file. fstReaderVarint32 copies attacker-controlled LEB128 bytes into a five-byte stack buffer until a byte clears its high bit, without enforcing the buffer limit. The gate is user interaction; successful exploitation runs code with the privileges of the GTKWave process and can compromise data or interrupt the process.
The record
- CVE
- CVE-2023-35702
- Published
- Jan 8, 2024
- Updated
- Nov 4, 2025
- Vendor
- GTKWave
- Product
- GTKWave
- Classifications
- CWE-121, 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 crafted FST varint exampleproof 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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