Stack disclosure via uninitialized redirect ticket
Published Oct 12, 2023 · Updated Nov 4, 2025
Information disclosure in SoftEther VPN 5.01.9674 allows man-in-the-middle attackers to read 20 bytes of uninitialized stack data. ClientConnect copies an uninitialized UCHAR ticket[20] when a clustering redirect omits its Ticket, then transmits those bytes to the redirect destination. Exploitation requires an authenticated client connection to an attacker-controlled server reached through traffic interception or DNS rewriting; enabled certificate verification also requires the legitimate server's private key.
Summary
What happened
Information disclosure in SoftEther VPN 5.01.9674 allows man-in-the-middle attackers to read 20 bytes of uninitialized stack data. ClientConnect copies an uninitialized UCHAR ticket[20] when a clustering redirect omits its Ticket, then transmits those bytes to the redirect destination. Exploitation requires an authenticated client connection to an attacker-controlled server reached through traffic interception or DNS rewriting; enabled certificate verification also requires the legitimate server's private key.
The record
- CVE
- CVE-2023-31192
- Published
- Oct 12, 2023
- Updated
- Nov 4, 2025
- Vendor
- SoftEther VPN Project
- Product
- SoftEther VPN
- Classifications
- CWE-457, T1557
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 12, 2023CVE 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?
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- Affected versionversion=5.01.9674
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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