CVE-2023-36747Public exploit

Memory corruption via unchecked FST signal length

Published Jan 8, 2024 · Updated Nov 4, 2025

Heap-based buffer overflow in GTKWave 3.3.115 allows attackers to corrupt memory by inducing a victim to open a crafted FST file. In fstReaderIterBlocks2, an attacker-controlled signal_lens value is passed as len to fstWritex, which supplies it to memcpy without checking it against the remaining mu + sig_offs buffer. The victim must open the file; a mismatched beg_time reaches this path, producing an out-of-bounds heap write with process-crash or code-execution impact.

CVSS severity7.0
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in GTKWave 3.3.115 allows attackers to corrupt memory by inducing a victim to open a crafted FST file. In fstReaderIterBlocks2, an attacker-controlled signal_lens value is passed as len to fstWritex, which supplies it to memcpy without checking it against the remaining mu + sig_offs buffer. The victim must open the file; a mismatched beg_time reaches this path, producing an out-of-bounds heap write with process-crash or code-execution impact.

The record

CVE
CVE-2023-36747
Published
Jan 8, 2024
Updated
Nov 4, 2025
Vendor
GTKWave
Product
GTKWave
Classifications
CWE-119, 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

7.0Cisco TalosCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS: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
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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