Arbitrary code execution via unchecked tdelta index
Published Jan 8, 2024 · Updated Nov 4, 2025
Heap out-of-bounds write in GTKWave 3.3.115 allows attackers to execute arbitrary code by inducing a user to open a crafted FST file. fstReaderIterBlocks2 uses the file-controlled tdelta value to index the tc_head array without checking it against the file-controlled tsec_nitems allocation. Execution requires a victim to open the file, after which the write can corrupt heap memory at an attacker-controlled offset.
Summary
What happened
Heap out-of-bounds write in GTKWave 3.3.115 allows attackers to execute arbitrary code by inducing a user to open a crafted FST file. fstReaderIterBlocks2 uses the file-controlled tdelta value to index the tc_head array without checking it against the file-controlled tsec_nitems allocation. Execution requires a victim to open the file, after which the write can corrupt heap memory at an attacker-controlled offset.
The record
- CVE
- CVE-2023-35994
- Published
- Jan 8, 2024
- Updated
- Nov 4, 2025
- Vendor
- GTKWave
- Product
- GTKWave
- Classifications
- CWE-129, 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
- Talos malformed FST demonstrationproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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